Cipher challenge #3 from Joshua Holden: Binary ciphers

The Mathematics of Secrets by Joshua Holden takes readers on a tour of the mathematics behind cryptography. Most books about cryptography are organized historically, or around how codes and ciphers have been used in government and military intelligence or bank transactions. Holden instead focuses on how mathematical principles underpin the ways that different codes and ciphers operate. Discussing the majority of ancient and modern ciphers currently known, The Mathematics of Secrets sheds light on both code making and code breaking. Over the next few weeks, we’ll be running a series of cipher challenges from Joshua Holden. The last post was on subliminal channels. Today’s is on binary ciphers:

Binary numerals, as most people know, represent numbers using only the digits 0 and 1.  They are very common in modern ciphers due to their use in computers, and they frequently represent letters of the alphabet.  A numeral like 10010 could represent the (1 · 24 + 0 · 23 + 0 · 22 + 1 · 2 + 0)th = 18th letter of the alphabet, or r.  So the entire alphabet would be:

 plaintext:   a     b     c     d     e     f     g     h     i     j
ciphertext: 00001 00010 00011 00100 00101 00110 00111 01000 01001 01010

 plaintext:   k     l     m     n     o     p     q     r     s     t
ciphertext: 01011 01100 01101 01110 01111 10000 10001 10010 10011 10100

 plaintext:   u     v     w     x     y     z
ciphertext: 10101 10110 10111 11000 11001 11010

The first use of a binary numeral system in cryptography, however, was well before the advent of digital computers. Sir Francis Bacon alluded to this cipher in 1605 in his work Of the Proficience and Advancement of Learning, Divine and Humane and published it in 1623 in the enlarged Latin version De Augmentis Scientarum. In this system not only the meaning but the very existence of the message is hidden in an innocuous “covertext.” We will give a modern English example.

Suppose we want to encrypt the word “not” into the covertext “I wrote Shakespeare.” First convert the plaintext into binary numerals:

   plaintext:   n      o     t
  ciphertext: 01110  01111 10100

Then stick the digits together into a string:

    011100111110100

Now we need what Bacon called a “biformed alphabet,” that is, one where each letter can have a “0-form” and a “1-form.”We will use roman letters for our 0-form and italic for our 1-form. Then for each letter of the covertext, if the corresponding digit in the ciphertext is 0, use the 0-form, and if the digit is 1 use the 1-form:

    0 11100 111110100xx
    I wrote Shakespeare.

Any leftover letters can be ignored, and we leave in spaces and punctuation to make the covertext look more realistic. Of course, it still looks odd with two different typefaces—Bacon’s examples were more subtle, although it’s a tricky business to get two alphabets that are similar enough to fool the casual observer but distinct enough to allow for accurate decryption.

Ciphers with binary numerals were reinvented many years later for use with the telegraph and then the printing telegraph, or teletypewriter. The first of these were technically not cryptographic since they were intended for convenience rather than secrecy. We could call them nonsecret ciphers, although for historical reasons they are usually called codes or sometimes encodings. The most well-known nonsecret encoding is probably the Morse code used for telegraphs and early radio, although Morse code does not use binary numerals. In 1833, Gauss, whom we met in Chapter 1, and the physicist Wilhelm Weber invented probably the first telegraph code, using essentially the same system of 5 binary digits as Bacon. Jean-Maurice-Émile Baudot used the same idea for his Baudot code when he invented his teletypewriter system in 1874. And the Baudot code is the one that Gilbert S. Vernam had in front of him in 1917 when his team at AT&T was asked to investigate the security of teletypewriter communications.

Vernam realized that he could take the string of binary digits produced by the Baudot code and encrypt it by combining each digit from the plaintext with a corresponding digit from the key according to the rules:

0 ⊕ 0 = 0
0 ⊕ 1 = 1
1 ⊕ 0 = 1
1 ⊕ 1 = 0

For example, the digits 10010, which ordinarily represent 18, and the digits 01110, which ordinarily represent 14, would be combined to get:

1 0 0 1 0
0 1 1 1 0


1 1 1 0 0

This gives 11100, which ordinarily represents 28—not the usual sum of 18 and 14.

Some of the systems that AT&T was using were equipped to automatically send messages using a paper tape, which could be punched with holes in 5 columns—a hole indicated a 1 in the Baudot code and no hole indicated a 0. Vernam configured the teletypewriter to combine each digit represented by the plaintext tape to the corresponding digit from a second tape punched with key characters. The resulting ciphertext is sent over the telegraph lines as usual.

At the other end, Bob feeds an identical copy of the tape through the same circuitry. Notice that doing the same operation twice gives you back the original value for each rule:

(0 ⊕ 0) ⊕ 0 = 0 ⊕ 0 = 0
(0 ⊕ 1) ⊕ 1 = 1 ⊕ 1 = 0
(1 ⊕ 0) ⊕ 0 = 1 ⊕ 0 = 1
(1 ⊕ 1) ⊕ 1 = 0 ⊕ 1 = 1

Thus the same operation at Bob’s end cancels out the key, and the teletypewriter can print the plaintext. Vernam’s invention and its further developments became extremely important in modern ciphers such as the ones in Sections 4.3 and 5.2 of The Mathematics of Secrets.

But let’s finish this post by going back to Bacon’s cipher.  I’ve changed it up a little — the covertext below is made up of two different kinds of words, not two different kinds of letters.  Can you figure out the two different kinds and decipher the hidden message?

It’s very important always to understand that students and examiners of cryptography are often confused in considering our Francis Bacon and another Bacon: esteemed Roger. It is easy to address even issues as evidently confusing as one of this nature. It becomes clear when you observe they lived different eras.

Answer to Cipher Challenge #2: Subliminal Channels

Given the hints, a good first assumption is that the ciphertext numbers have to be combined in such a way as to get rid of all of the fractions and give a whole number between 1 and 52.  If you look carefully, you’ll see that 1/5 is always paired with 3/5, 2/5 with 1/5, 3/5 with 4/5, and 4/5 with 2/5.  In each case, twice the first one plus the second one gives you a whole number:

2 × (1/5) + 3/5 = 5/5 = 1
2 × (2/5) + 1/5 = 5/5 = 1
2 × (3/5) + 4/5 = 10/5 = 2
2 × (4/5) + 2/5 = 10/5 = 2

Also, twice the second one minus the first one gives you a whole number:

2 × (3/5) – 1/5 = 5/5 = 1
2 × (1/5) – 2/5 = 0/5 = 0
2 × (4/5) – 3/5 = 5/5 = 1
2 × (2/5) – 4/5 = 0/5 = 0

Applying

to the ciphertext gives the first plaintext:

39 31 45 45 27 33 31 40 47 39 28 31 44 41
 m  e  s  s  a  g  e  n  u  m  b  e  r  o
40 31 35 45 46 34 31 39 31 30 35 47 39
 n  e  i  s  t  h  e  m  e  d  i  u  m

And applying

to the ciphertext gives the second plaintext:

20  8  5 19  5  3 15 14  4 16 12  1  9 14 
 t  h  e  s  e  c  o  n  d  p  l  a  i  n
20  5 24 20  9 19  1 20 12  1 18  7  5
 t  e  x  t  i  s  a  t  l  a  r  g  e

To deduce the encryption process, we have to solve our two equations for C1 and C2.  Subtracting the second equation from twice the first gives:


so

Adding the first equation to twice the second gives:


so

Joshua Holden is professor of mathematics at the Rose-Hulman Institute of Technology.

Browse Our Mathematics 2017 Catalog

Be among the first to browse our Mathematics 2017 Catalog:

If you are heading to the 2017 Joint Mathematics Meetings in Atlanta, Georgia from January 4 to January 7, come visit us at booth #143 to enter daily book raffles, challenge the SET grand master in a SET match, and receive a free copy of The Joy of SET if you win! Please visit our booth for the schedule.

Also, follow #JMM17 and @PrincetonUnivPress on Twitter for updates and information on our new and forthcoming titles throughout the meeting.

Fibonacci helped to revive the West as the cradle of science, technology, and commerce, yet he vanished from the pages of history. Finding Fibonacci is Keith Devlin’s compelling firsthand account of his ten-year quest to tell Fibonacci’s story.

Devlin Fibonacci cover

This annual anthology brings together the year’s finest mathematics writing from around the world. Featuring promising new voices alongside some of the foremost names in the field, The Best Writing on Mathematics 2016 makes available to a wide audience many articles not easily found anywhere else—and you don’t need to be a mathematician to enjoy them.

Pitici Best writing on Maths

In The Calculus of Happiness, Oscar Fernandez shows us that math yields powerful insights into health, wealth, and love. Using only high-school-level math, he guides us through several of the surprising results, including an easy rule of thumb for choosing foods that lower our risk for developing diabetes, simple “all-weather” investment portfolios with great returns, and math-backed strategies for achieving financial independence and searching for our soul mate.

Fernandez Calculus of Happiness

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Joshua Holden: The secrets behind secret messages

“Cryptography is all about secrets, and throughout most of its history the whole field has been shrouded in secrecy.  The result has been that just knowing about cryptography seems dangerous and even mystical.”

In The Mathematics of Secrets: Cryptography from Caesar Ciphers to Digital EncryptionJoshua Holden provides the mathematical principles behind ancient and modern cryptic codes and ciphers. Using famous ciphers such as the Caesar Cipher, Holden reveals the key mathematical idea behind each, revealing how such ciphers are made, and how they are broken.  Holden recently took the time to answer questions about his book and cryptography.


There are lots of interesting things related to secret messages to talk abouthistory, sociology, politics, military studies, technology. Why should people be interested in the mathematics of cryptography? 
 
JH: Modern cryptography is a science, and like all modern science it relies on mathematics.  If you want to really understand what modern cryptography can and can’t do you need to know something about that mathematical foundation. Otherwise you’re just taking someone’s word for whether messages are secure, and because of all those sociological and political factors that might not be a wise thing to do. Besides that, I think the particular kinds of mathematics used in cryptography are really pretty. 
 
What kinds of mathematics are used in modern cryptography? Do you have to have a Ph.D. in mathematics to understand it? 
 
JH: I once taught a class on cryptography in which I said that the prerequisite was high school algebra.  Probably I should have said that the prerequisite was high school algebra and a willingness to think hard about it.  Most (but not all) of the mathematics is of the sort often called “discrete.”  That means it deals with things you can count, like whole numbers and squares in a grid, and not with things like irrational numbers and curves in a plane.  There’s also a fair amount of statistics, especially in the codebreaking aspects of cryptography.  All of the mathematics in this book is accessible to college undergraduates and most of it is understandable by moderately advanced high school students who are willing to put in some time with it. 
 
What is one myth about cryptography that you would like to address? 
 
JH: Cryptography is all about secrets, and throughout most of its history the whole field has been shrouded in secrecy.  The result has been that just knowing about cryptography seems dangerous and even mystical. In the Renaissance it was associated with black magic and a famous book on cryptography was banned by the Catholic Church. At the same time, the Church was using cryptography to keep its own messages secret while revealing as little about its techniques as possible. Through most of history, in fact, cryptography was used largely by militaries and governments who felt that their methods should be hidden from the world at large. That began to be challenged in the 19th century when Auguste Kerckhoffs declared that a good cryptographic system should be secure with only the bare minimum of information kept secret. 
 
Nowadays we can relate this idea to the open-source software movement. When more people are allowed to hunt for “bugs” (that is, security failures) the quality of the overall system is likely to go up. Even governments are beginning to get on board with some of the systems they use, although most still keep their highest-level systems tightly classified. Some professional cryptographers still claim that the public can’t possibly understand enough modern cryptography to be useful. Instead of keeping their writings secret they deliberately make it hard for anyone outside the field to understand them. It’s true that a deep understanding of the field takes years of study, but I don’t believe that people should be discouraged from trying to understand the basics. 
 
I invented a secret code once that none of my friends could break. Is it worth any money? 
 
JH: Like many sorts of inventing, coming up with a cryptographic system looks easy at first.  Unlike most inventions, however, it’s not always obvious if a secret code doesn’t “work.” It’s easy to get into the mindset that there’s only one way to break a system so all you have to do is test that way.  Professional codebreakers know that on the contrary, there are no rules for what’s allowed in breaking codes. Often the methods for codebreaking with are totally unsuspected by the codemakers. My favorite involves putting a chip card, such as a credit card with a microchip, into a microwave oven and turning it on. Looking at the output of the card when bombarded 
by radiation could reveal information about the encrypted information on the card! 
 
That being said, many cryptographic systems throughout history have indeed been invented by amateurs, and many systems invented by professionals turned out to be insecure, sometimes laughably so. The moral is, don’t rely on your own judgment, anymore than you should in medical or legal matters. Get a second opinion from a professional you trustyour local university is a good place to start.   
 
A lot of news reports lately are saying that new kinds of computers are about to break all of the cryptography used on the Internet. Other reports say that criminals and terrorists using unbreakable cryptography are about to take over the Internet. Are we in big trouble? 
 
JH: Probably not. As you might expect, both of these claims have an element of truth to them, and both of them are frequently blown way out of proportion. A lot of experts do expect that a new type of computer that uses quantum mechanics will “soon” become a reality, although there is some disagreement about what “soon” means. In August 2015 the U.S. National Security Agency announced that it was planning to introduce a new list of cryptography methods that would resist quantum computers but it has not announced a timetable for the introduction. Government agencies are concerned about protecting data that might have to remain secure for decades into the future, so the NSA is trying to prepare now for computers that could still be 10 or 20 years into the future. 
 
In the meantime, should we worry about bad guys with unbreakable cryptography? It’s true that pretty much anyone in the world can now get a hold of software that, when used properly, is secure against any publicly known attacks. The key here is “when used properly. In addition to the things I mentioned above, professional codebreakers know that hardly any system is always used properly. And when a system is used improperly even once, that can give an experienced codebreaker the information they need to read all the messages sent with that system.  Law enforcement and national security personnel can put that together with information gathered in other waysurveillance, confidential informants, analysis of metadata and transmission characteristics, etc.and still have a potent tool against wrongdoers. 
 
There are a lot of difficult political questions about whether we should try to restrict the availability of strong encryption. On the flip side, there are questions about how much information law enforcement and security agencies should be able to gather. My book doesn’t directly address those questions, but I hope that it gives readers the tools to understand the capabilities of codemakers and codebreakers. Without that you really do the best job of answering those political questions.

Joshua Holden is professor of mathematics at the Rose-Hulman Institute of Technology in Terre Haute, IN. His most recent book is The Mathematics of Secrets: Cryptography from Caesar Ciphers to Digital Encryption.

This Halloween, a few books that won’t (shouldn’t!) die

If Halloween has you looking for a way to combine your love (or terror) of zombies and academic books, you’re in luck: Princeton University Press has quite a distinguished publishing history when it comes to the undead.

 

As you noticed if you follow us on Instagram, a few of our favorites have come back to haunt us this October morning. What is this motley crew of titles doing in a pile of withered leaves? Well, The Origins of Monsters offers a peek at the reasons behind the spread of monstrous imagery in ancient empires; Zombies and Calculus  features a veritable course on how to use higher math skills to survive the zombie apocalypse, and International Politics and Zombies invites you to ponder how well-known theories from international relations might be applied to a war with zombies. Is neuroscience your thing? Do Zombies Dream of Undead Sheep? shows how zombism can be understood in terms of current knowledge regarding how the brain works. Or of course, you can take a trip to the graveyard of economic ideology with Zombie Economics, which was probably off marauding when this photo was snapped.

If you’re feeling more ascetic, Black: The History of a Color tells the social history of the color black—archetypal color of darkness and death—but also, Michel Pastoureau tells us, monastic virtue. A strikingly designed choice:

In the beginning was black, Michel Pastoureau tells us in Black: A History of a Color

A post shared by Princeton University Press (@princetonupress) on

 

Happy Halloween, bookworms.

Peter Dougherty & Al Bertrand: On Being Einstein’s Publisher

by Peter Dougherty and Al Bertrand

So many people today—and even professional scientists—seem to me like somebody who has seen thousands of trees but has never seen a forest. (Albert Einstein to Robert A Thornton, 7 December 1944, EA 61-574)

For all of the scholarly influences that have defined Princeton University Press over its 111-year history, no single personality has shaped the Press’s identity as powerfully, both directly and indirectly, as Albert Einstein. The 2015 centenary of the publication of Einstein’s “Theory of General Relativity” as well as the affirmation this past February and again in June of the discovery of gravitational waves has encouraged us to reflect on this legacy and how it has informed our identity as a publisher.

The bright light cast by Einstein the scientist and by Einstein the humanist has shaped Princeton University Press in profound and far-reaching ways. It expresses itself in the Press’s standard of scholarly excellence, its emphasis on the breadth and connectedness of liberal learning across all fields, and in our mission of framing scholarly arguments to shape contemporary knowledge. All the while, Einstein’s role as a citizen of the world inspires our vision to be a truly global university press.

PUBLISHING EINSTEIN: A BRIEF HISTORY

Albert Einstein is not only Princeton University Press’s most illustrious author; he was our first best-selling author. Following his public lectures in Princeton in 1921, the Press—itself less than 20 years old at the time—published the text of those lectures, titled “The Meaning of Relativity”, in 1922. Publication followed the agitated exhortation of the Press’s then-manager, Frank Tomlinson, urging Professor Einstein to get his manuscript finished. Tomlinson wrote:

My dear Professor Einstein—

On July 6 I wrote you inquiring when we might expect to receive the manuscript of your lectures. I have had no reply to this letter. A number of people have been inquiring when the book will be ready, and we are considerably alarmed at the long delay in the receipt of your manuscript, which we were led to believe would be in our hands within a month after the lectures were delivered. The importance of the book will undoubtedly be seriously affected unless we are able to publish it within a reasonable time and I strongly urge upon you the necessity of sending us the copy at your earliest convenience. I should appreciate also the favor of a reply from you stating when we may expect to receive it.

the meaning of relativity jacketMr. Tomlinson’s letter marks something of a high point in the history of publishers’ anxiety, but far from failing, The Meaning of Relativity was a hit. It would go on to numerous successive editions, and remains very much alive today as both a print and digital book, as well as in numerous translated editions.

For all its glorious publishing history, The Meaning of Relativity can be thought of as a mere appetizer to the bounteous publishing banquet embodied in THE COLLECTED PAPERS OF ALBERT EINSTEIN, surely PUP’s most ambitious continuing publication and one of the most important editorial projects in all of scholarly publishing.

The Collected Papers of Albert Einstein

Authorized by the Einstein Estate and the PUP Board of Trustees in 1970, and supported by a generous grant from the late Harold W. McGraw, Jr., chairman of the McGraw-Hill Book Company, THE EINSTEIN PAPERS, as it evolves, is providing the first complete and authoritative account of a written legacy that ranges from Einstein’s work on the special and general theories of relativity and the origins of quantum theory, to expressions of his profound concern with civil liberties, education, Zionism, pacifism, and disarmament.

einstein old letterAn old saying has it that “good things come to those to wait,” words that ring resoundingly true regarding the EINSTEIN PAPERS. Having survived multiple obstacles in the long journey from its inception through the publication of its first volume in 1987, the Einstein Papers Project hit its stride in 2000 when Princeton University Press engaged Professor Diana Buchwald as its sixth editor, and moved the Project to Pasadena with the generous support of its new host institution, the California Institute of Technology.

Since then, Professor Buchwald and her Caltech-based editorial team, along with their international network of scholarly editors, have produced successive documentary and English translation volumes at the rate of one every eighteen months. To give you an idea of just how impressive a pace this is, the Galileo papers are still a work in progress, nearly four centuries after his death.

The EINSTEIN PAPERS, having reached and documented Einstein’s writings up to 1925, has fundamentally altered our understanding of the history of physics and of the development of general relativity, for example by destroying the myth of Einstein as a lone genius and revealing the extent to which this man, with his great gift for friendship and collegiality, was embedded in a network of extraordinary scientists in Zurich, Prague, and Berlin.

Along with the EINSTEIN PAPERS, the Press has grown a lively publishing program of books drawn from his work and about Einstein. Satellite projects include The Ultimate Quotable Einstein, as well as volumes on Einstein’s politics, his love letters, and the “miraculous year” of 1905.

Last year the Press published two new books drawn from Einstein’s writings, The Road to Relativity, and the 100th anniversary edition of Relativity: The Special and General Theory, both volumes edited by Jürgen Renn of the Max Planck Institute in Berlin, and Hanoch Gutfreund of the Hebrew University in Jerusalem.   These volumes celebrate the centenary of Einstein’s publication of the theory of general relativity in November 1915.

In this same centenary year, PUP published several other Einstein titles, including:

— Volume 14 of the Collected Papers, The Berlin Years, 1923-1925.

An Einstein Encyclopedia, edited by Alice Calaprice, Daniel Kennefick, and Robert Schulman;

Einstein: A Hundred Years of Relativity, by Andrew Robinson

Especially notable, in January 2015 the Press released THE DIGITAL EDITION OF THE COLLECTED PAPERS OF ALBERT EINSTEIN, a publishing event that has attracted extraordinary worldwide attention, scientific as well as public. This online edition is freely available to readers and researchers around the world, and represents the historic collaboration between the Press and its partners, the Einstein Papers Project at Caltech and the Albert Einstein Archive in the Hebrew University in Jerusalem.

Moreover, works by and about Einstein sit at the crossroads of two major components of the Princeton list: our science publishing program which comprises a host of fields from physics through mathematics, biology, earth science, computer science, and natural history, and our history of science program which connects PUP’s Einstein output to our humanities publishing, helping to bridge the intellectual gap between two major dimensions of our list.

Einstein’s dual legacy at Princeton University Press thus serves to bookend the conversation defined by the Press’s unusually wide-ranging array of works across and throughout the arts and sciences, from mathematics to poetry. C.P. Snow famously described the sciences and the humanities as “two cultures.” Einstein’s legacy informs our effort as a publisher to create an ongoing correspondence between those two cultures in the form of books, which uniquely serve to synthesize, connect, and nurture cross-disciplinary discourse.

EINSTEIN’S LARGER PUBLISHING INFLUENCE

Much as the living legacy of the EINSTEIN PAPERS and its related publications means to Princeton University Press as a publisher, it holds a broader meaning for us both as editors and as leaders of the institution with which we’ve long been affiliated.

Like most of our colleagues, we arrived at the Press as editors previously employed by other publishers, and having little professional interest in physics. Each of us specialized in different editorial fields, economics and classics, respectively.

Our initial disposition towards the field of physics, while full of awe, was perhaps best summed up by Woody Allen when he said: “I’m astounded by people who want to ‘know’ the universe when it’s hard enough to find your way around Chinatown.”  

But we soon discovered, as newcomers to PUP inevitably do, that the Princeton publishing legacy of Albert Einstein carried with it a set of implications beyond his specific scientific bounty that would help to shape our publishing activity, as well as that of our colleagues. We see the Einstein legacy operating in three distinct ways on PUP’s culture:

First, it reinforces the centrality of excellence as a standard: simply put, we strive to publish the core scholarly books by leading authors, senior as well as first-time. Einstein’s legacy stands as a giant-sized symbol of excellence, an invisible but constant reminder that our challenge as publishers at Princeton is not merely to be good, but to be great. As we seek greatness by publishing those books that help to define and unite the frontiers of modern scholarship, and connect our authors’ ideas with minds everywhere, we are upholding a standard embodied in the work of Albert Einstein.

The second implication of the bounty Albert Einstein is a commitment to seeing liberal knowledge defined broadly, encompassing its scientific articulation as well as its expression in the humanities and social sciences. PUP purposefully publishes an unusually wide portfolio of subject areas, encompassing not only standard university press fields such as literary criticism, art history, politics, sociology, and philosophy, but a full complement of technical fields, including biology, physics, neuroscience, mathematics, economics, and computer science. A rival publisher once half-jokingly described PUP as “the empirical knowledge capital of the world.” She was referring to our capacious cultivation of scientific and humanistic publishing, an ambitious menu for a publisher producing only around 250 books a year, but one we think gives the Press its distinctive identity.

It is no coincidence that Albert Einstein, PUP’s most celebrated author, cast his influence across many of these fields both as a scientist and as a humanist, engaged fully in the life of the mind and of the world. His legacy thus inspires us to concentrate our editorial energies on building a list that focuses on knowledge in its broadest and deepest sense—that puts into play the sometimes contentious, and even seemingly incongruous, methodologies of science and the humanities and articulates a broad yet rigorous, intellectual vision, elevating knowledge for its own sake, even as the issues change from decade to decade.

A third implication appears in Einstein’s challenge to us to be a great global publisher. Einstein, a self-professed “citizen of the world” was in many ways the first global citizen, a scholar whose scientific achievement and fame played out on a truly global scale in an age of parochial and often violent nationalist thinking.

Einstein’s cosmopolitanism has inspired the Press to pursue a path of becoming a truly global university Press. To do this, PUP has built lists in fields that are cosmopolitan in their readership, opened offices in Europe and China, expanded its author and reviewer base all over the world, and has licensed its content for translation in many languages. As we go forward, we intend to continue to build a network that allows us to connect many local publishing and academic cultures with the global scholarly conversation. This vision of the Press’s future echoes Einstein’s call for a science that transcends national boundaries.

THE FUTURE

It has been nearly a century since publication of The Meaning of Relativity and half that since the original agreement for the EINSTEIN PAPERS was authorized. We can only imagine that the originators of the latter project would be proud of what our collective effort has produced, grateful to the principals for the job they have done in bringing the PAPERS to their current status, and maybe above all, awed by the global exposure the PAPERS have achieved in their print and now digital formats.

As we continue our work with our colleagues at Caltech and the Hebrew University to extend the EINSTEIN PAPERS into the future, we are reminded of the significance of the great scientist’s legacy, especially as it bears on our identity as a global publisher, framing the pursuit of knowledge imaginatively across the arts and sciences.

The eminent Italian publisher Roberto Calasso, in his recent book, The Art of the Publisher, encourages readers to imagine a publishing house as,

“a single text formed not just by the totality of books that have been published there, but also by its other constituent elements, such as the front covers, cover flaps, publicity, the quantity of copies printed and sold, or the different editions in which the same text has been presented. Imagine a publishing house in this way and you will find yourself immersed in a very strange landscape, something that you might regard as a literary work in itself, belonging to a genre all its own.”

Now, at a time when the very definition of publishing is being undermined by technological and economic forces, it is striking to see each publisher as a “literary work unto itself.” So it is with Princeton University Press. In so far as PUP can claim a list having a diversified but well-integrated publishing vision, one that constantly strives for excellence and that stresses the forest for the trees, it is inescapably about the spirit and substance reflected in the legacy of Albert Einstein, and it is inseparable from it.

Einstein_blog (small)

 


 

Peter J. Dougherty is Director of Princeton University Press. This essay is based in part on comments he delivered at the Space-Time Theories conference at the Hebrew University in Jerusalem in January, 2015. Al Bertrand is Associate Publishing Director of Princeton University Press and Executive Editor of the Press’s history of science publishing program, including Einstein-related publications.

Happy Birthday, Alan Turing

Hodges_AlanTuring movie tie inThursday, June 23rd marks the birthday of Alan Turing, widely credited with being the father of the modern computer and artificial intelligence, as well as with leading the Bletchley Park codebreakers in cracking an encryption method used by the Nazi’s. PUP is proud to have published Alan Turing: The Enigma, a scientific biography of the famous cryptologist that went on to become a New York Times Bestseller, and was adapted in the 2014 historical drama/thriller The Imitation Game. The film was a commercial and critical success, grossing over $233 million worldwide. Turing is, for many, a modern day mathematical hero in the spirit of Albert Einstein or John Nash.

Yet despite his genius and groundbreaking accomplishments, Turing was hounded to his early death about his sexuality. After facing a 1952 charge of indecency over his relationship with another man, a criminal act in the UK at the time, he endured chemical castration and took his own life only two years later at age 41.

Archaic attitudes and inhumane treatment of LGBT people continued by the agency (and more broadly in society) for decades after Turing’s death. But in a historic move this past April, the GCHQ (UK Government Communications Headquarters) issued a formal apology, acknowledging that the treatment of Turing was “horrifying”.

You can read more about the apology here.

A man who changed the modern world while anticipating gay liberation by decades, Turing’s tragically brief four decades of life were unarguably well spent. Happy birthday, Alan Turing.

An interview with John Stillwell on Elements of Mathematics

elements of mathematics jacketNot all topics that are part of today’s elementary mathematics were always considered as such, and great mathematical advances and discoveries had to occur in order for certain subjects to become “elementary.” Elements of Mathematics: From Euclid to Gödel, by John Stillwell gives readers, from high school students to professional mathematicians, the highlights of elementary mathematics and glimpses of the parts of math beyond its boundaries.

You’ve been writing math books for a long time now. What do you think is special about this one?

JS: In some ways it is a synthesis of ideas that occur fleetingly in some of my previous books: the interplay between numbers, geometry, algebra, infinity, and logic. In all my books I try to show the interaction between different fields of mathematics, but this is one more unified than any of the others. It covers some fields I have not covered before, such as probability, but also makes many connections I have not made before. I would say that it is also more reflective and philosophical—it really sums up all my experience in mathematics.

Who do you expect will enjoy reading this book?

JS: Well I hope my previous readers will still be interested! But for anyone who has not read my previous work, this might be the best place to start. It should suit anyone who is broadly interested in math, from high school to professional level. For the high school students, the book is a guide to the math they will meet in the future—they may understand only parts of it, but I think it will plant seeds for their future mathematical development. For the professors—I believe there will be many parts that are new and enlightening, judging from the number of times I have often heard “I never knew that!” when speaking on parts of the book to academic audiences.

Does the “Elements” in the title indicate that this book is elementary?

JS: I have tried to make it as simple as possible but, as Einstein is supposed to have said, “not simpler”. So, even though it is mainly about elementary mathematics it is not entirely elementary. It can’t be, because I also want to describe the limits of elementary mathematics—where and why mathematics becomes difficult. To get a realistic appreciation of math, it helps to know that some difficulties are unavoidable. Of course, for mathematicians, the difficulty of math is a big attraction.

What is novel about your approach?

JS: It tries to say something precise and rigorous about the boundaries of elementary math. There is now a field called “reverse mathematics” which aims to find exactly the right axioms to prove important theorems. For example, it has been known for a long time—possibly since Euclid—that the parallel axiom is the “right” axiom to prove the Pythagorean theorem. Much more recently, reverse mathematics has found that certain assumptions about infinity are the right axioms to prove basic theorems of analysis. This research, which has only appeared in specialist publications until now, helps explain why infinity appears so often at the boundaries of elementary math.

Does your book have real world applications?

JS: Someone always asks that question. I would say that if even one person understands mathematics better because of my book, then that is a net benefit to the world. The modern world runs on mathematics, so understanding math is necessary for anyone who wants to understand the world.

John Stillwell is professor of mathematics at the University of San Francisco. His many books include Mathematics and Its History and Roads to Infinity. His most recent book is Elements of Mathematics: From Euclid to Gödel.

Nicholas J. Higham: The Top 10 Algorithms in Applied Mathematics

pcam-p346-newton.jpg

From “Computational Science” by David E. Keyes in Princeton Companion to Applied Mathematics

In the January/February 2000 issue of Computing in Science and Engineering, Jack Dongarra and Francis Sullivan chose the “10
algorithms with the greatest influence on the development and practice of science and engineering in the 20th century” and presented a group of articles on them that they had commissioned and edited. (A SIAM News article by Barry Cipra gives a summary for anyone who does not have access to the original articles). This top ten list has attracted a lot of interest.

Sixteen years later, I though it would be interesting to produce such a list in a different way and see how it compares with the original top ten. My unscientific—but well defined— way of doing so is to determine which algorithms have the most page locators in the index of The Princeton Companion to Applied Mathematics (PCAM). This is a flawed measure for several reasons. First, the book focuses on applied mathematics, so some algorithms included in the original list may be outside its scope, though the book takes a broad view of the subject and includes many articles about applications and about topics on the interface with other areas. Second, the content is selective and the book does not attempt to cover all of applied mathematics. Third, the number of page locators is not necessarily a good measure of importance. However, the index was prepared by a professional indexer, so it should reflect the content of the book fairly objectively.

A problem facing anyone who compiles such a list is to define what is meant by “algorithm”. Where does one draw the line between an algorithm and a technique? For a simple example, is putting a rational function in partial fraction form an algorithm? In compiling the following list I have erred on the side of inclusion. This top ten list is in decreasing order of the number of page locators.

  1. Newton and quasi-Newton methods
  2. Matrix factorizations (LU, Cholesky, QR)
  3. Singular value decomposition, QR and QZ algorithms
  4. Monte-Carlo methods
  5. Fast Fourier transform
  6. Krylov subspace methods (conjugate gradients, Lanczos, GMRES,
    minres)
  7. JPEG
  8. PageRank
  9. Simplex algorithm
  10. Kalman filter

Note that JPEG (1992) and PageRank (1998) were youngsters in 2000, but all the other algorithms date back at least to the 1960s.

By comparison, the 2000 list is, in chronological order (no other ordering was given)

  • Metropolis algorithm for Monte Carlo
  • Simplex method for linear programming
  • Krylov subspace iteration methods
  • The decompositional approach to matrix computations
  • The Fortran optimizing compiler
  • QR algorithm for computing eigenvalues
  • Quicksort algorithm for sorting
  • Fast Fourier transform
  • Integer relation detection
  • Fast multipole method

The two lists agree in 7 of their entries. The differences are:

PCAM list 2000 list
Newton and quasi-Newton methods The Fortran Optimizing Compiler
Jpeg Quicksort algorithm for sorting
PageRank Integer relation detection
Kalman filter Fast multipole method

Of those in the right-hand column, Fortran is in the index of PCAM and would have made the list, but so would C, MATLAB, etc., and I draw the line at including languages and compilers; the fast multipole method nearly made the PCAM table; and quicksort and integer relation detection both have one page locator in the PCAM index.

There is a remarkable agreement between the two lists! Dongarra and Sullivan say they knew that “whatever we came up with in the end, it would be controversial”. Their top ten has certainly stimulated some debate, but I don’t think it has been too controversial. This comparison suggests that Dongarra and Sullivan did a pretty good job, and one that has stood the test of time well.

Finally, I point readers to a talk Who invented the great numerical algorithms? by Nick Trefethen for a historical perspective on algorithms, including most of those mentioned above.

This post originally appeared on Higham’s popular website.

Higham jacketNicholas J. Higham is the Richardson Professor of Applied Mathematics at The University of Manchester. He most recently edited The Princeton Companion to Applied Mathematics.

Happy Birthday, Albert Einstein!

What a year. Einstein may have famously called his own birthday a natural disaster, but between the discovery of gravitational waves in February and the 100th anniversary of the general theory of relativity this past November, it’s been a big year for the renowned physicist and former Princeton resident. Throughout the day, PUP’s design blog will be celebrating with featured posts on our Einstein books and the stories behind them.

HappyBirthdayEinstein Graphic 3

Here are some of our favorite Einstein blog posts from the past year:

Was Einstein the First to Discover General Relativity? by Daniel Kennefick

Under the Spell of Relativity by Katherine Freese

Einstein: A Missionary of Science by Jürgen Renn

Me, Myself and Einstein by Jimena Canales

The Revelation of Relativity by Hanoch Gutfreund

A Mere Philosopher by Eoghan Barry

The Final Days of Albert Einstein by Debra Liese

 

Praeteritio and the quiet importance of Pi

pidayby James D. Stein

Somewhere along my somewhat convoluted educational journey I encountered Latin rhetorical devices. At least one has become part of common usage–oxymoron, the apparent paradox created by juxtaposed words which seem to contradict each other; a classic example being ‘awfully good’. For some reason, one of the devices that has stuck with me over the years is praeteritio, in which emphasis is placed on a topic by saying that one is omitting it. For instance, you could say that when one forgets about 9/11, the Iraq War, Hurricane Katrina, and the Meltdown, George W. Bush’s presidency was smooth sailing.

I’ve always wanted to invent a word, like John Allen Paulos did with ‘innumeracy’, and πraeteritio is my leading candidate–it’s the fact that we call attention to the overwhelming importance of the number π by deliberately excluding it from the conversation. We do that in one of the most important formulas encountered by intermediate algebra and trigonometry students; s = rθ, the formula for the arc length s subtended by a central angle θ in a circle of radius r.

You don’t see π in this formula because π is so important, so natural, that mathematicians use radians as a measure of angle, and π is naturally incorporated into radian measure. Most angle measurement that we see in the real world is described in terms of degrees. A full circle is 360 degrees, a straight angle 180 degrees, a right angle 90 degrees, and so on. But the circumference of a circle of radius 1 is 2π, and so it occurred to Roger Cotes (who is he? I’d never heard of him) that using an angular measure in which there were 2π angle units in a full circle would eliminate the need for a ‘fudge factor’ in the formula for the arc length of a circle subtended by a central angle. For instance, if one measured the angle D in degrees, the formula for the arc length of a circle of radius r subtended by a central angle would be s = (π/180)rD, and who wants to memorize that? The word ‘radian’ first appeared in an examination at Queen’s College in Belfast, Ireland, given by James Thomson, whose better-known brother William would later be known as Lord Kelvin.

The wisdom of this choice can be seen in its far-reaching consequences in the calculus of the trigonometric functions, and undoubtedly elsewhere. First semester calculus students learn that as long as one uses radian measure for angles, the derivative of sin x is cos x, and the derivative of cos x is – sin x. A standard problem in first-semester calculus, here left to the reader, is to compute what the derivative of sin x would be if the angle were measured in degrees rather than radians. Of course, the fudge factor π/180 would raise its ugly head, its square would appear in the formula for the second derivative of sin x, and instead of the elegant repeating pattern of the derivatives of sin x and cos x that are a highlight of the calculus of trigonometric functions, the ensuing formulas would be beyond ugly.

One of the simplest known formulas for the computation of π is via the infinite series 𝜋4=1−13+15−17+⋯

This deliciously elegant formula arises from integrating the geometric series with ratio -x^2 in the equation 1/(1+𝑥^2)=1−𝑥2+𝑥4−𝑥6+⋯

The integral of the left side is the inverse tangent function tan-1 x, but only because we have been fortunate enough to emphasize the importance of π by utilizing an angle measurement system which is the essence of πraeteritio; the recognition of the importance of π by excluding it from the discussion.

So on π Day, let us take a moment to recognize not only the beauty of π when it makes all the memorable appearances which we know and love, but to acknowledge its supreme importance and value in those critical situations where, like a great character in a play, it exerts a profound dramatic influence even when offstage.

LA MathJames D. Stein is emeritus professor in the Department of Mathematics at California State University, Long Beach. His books include Cosmic Numbers (Basic) and How Math Explains the World (Smithsonian). His most recent book is L.A. Math: Romance, Crime, and Mathematics in the City of Angels.

Where would we be without Pi?

Pi Day, the annual celebration of the mathematical constant π (pi), is always an excuse for mathematical and culinary revelry in Princeton. Since 3, 1, and 4 are the first three significant digits of π, the day is typically celebrated on 3/14, which in a stroke of serendipity, also happens to be Albert Einstein’s birthday. Pi Day falls on Monday this year, but Princeton has been celebrating all weekend with many more festivities still to come, from a Nerd Herd smart phone pub crawl, to an Einstein inspired running event sponsored by the Princeton Running Company, to a cocktail making class inside Einstein’s first residence. We imagine the former Princeton resident would be duly impressed.

Einstein enjoying a birthday/ Pi Day cupcake

Einstein enjoying a birthday/ Pi Day cupcake

Pi Day in Princeton always includes plenty of activities for children, and tends to be heavy on, you guessed it, actual pie (throwing it, eating it, and everything in between). To author Paul Nahin, this is fitting. At age 10, his first “scientific” revelation was,  If pi wasn’t around, there would be no round pies! Which it turns out, is all too true. Nahin explains:

Everybody “knows’’ that pi is a number a bit larger than 3 (pretty close to 22/7, as Archimedes showed more than 2,000 years ago) and, more accurately, is 3.14159265… But how do we know the value of pi? It’s the ratio of the circumference of a circle to a diameter, yes, but how does that explain how we know pi to hundreds of millions, even trillions, of decimal digits? We can’t measure lengths with that precision. Well then, just how do we calculate the value of pi? The symbol π (for pi) occurs in countless formulas used by physicists and other scientists and engineers, and so this is an important question. The short answer is, through the use of an infinite series expansion.

NahinIn his book In Praise of Simple Physics, Nahin shows you how to derive such a series that converges very quickly; the sum of just the first 10 terms correctly gives the first five digits. The English astronomer Abraham Sharp (1651–1699) used the first 150 terms of the series (in 1699) to calculate the first 72 digits of pi. That’s more than enough for physicists (and for anybody making round pies)!

While celebrating Pi Day has become popular—some would even say fashionable in nerdy circles— PUP author Marc Chamberland points out that it’s good to remember Pi, the number. With a basic scientific calculator, Chamberland’s recent video “The Easiest Way to Calculate Pi” details a straightforward approach to getting accurate approximations for Pi without tables or a prodigious digital memory. Want even more Pi? Marc’s book Single Digits has more than enough Pi to gorge on.

Now that’s a sweet dessert.

If you’re looking for more information on the origin of Pi, this post gives an explanation extracted from Joseph Mazur’s fascinating history of mathematical notation, Enlightening Symbols.

You can find a complete list of Pi Day activities from the Princeton Tour Company here.

Solving last week’s L.A. Math challenge

LA MathWe’re back with the conclusion to last week’s LA Math challenge, The Case of the Vanishing Greenbacks, (taken from chapter 2 of the book). After the conclusion of the story, we’ll talk a little more with the author, Jim Stein. Don’t forget to check out the fantastic trailer for LA Math here.

Forty‑eight hours later I was bleary‑eyed from lack of sleep. I had made no discernible progress. As far as I could tell, both Stevens and Blaisdell were completely on the up‑and‑up.   Either I was losing my touch, or one (or both) of them were wasting their talents, doctoring books for penny‑ante amounts.   Then I remembered the envelope Pete had sealed. Maybe he’d actually seen something that I hadn’t.

I went over to the main house, to find Pete hunkered down happily watching a baseball game. I waited for a commercial break, and then managed to get his attention.

“I’m ready to take a look in the envelope, Pete.”

“Have you figured out who the guilty party is?”

“Frankly, no. To be honest, it’s got me stumped.” I moved to the mantel and unsealed the envelope. The writing was on the other side of the piece of paper. I turned it over. The name Pete had written on it was “Garrett Ryan and the City Council”!

I nearly dropped the piece of paper. Whatever I had been expecting, it certainly wasn’t this. “What in heaven’s name makes you think Ryan and the City Council embezzled the money, Pete?”

“I didn’t say I thought they did. I just think they’re responsible for the missing funds.”

I shook my head. “I don’t get it. How can they be responsible for the missing funds if they didn’t embezzle them?”

“They’re probably just guilty of innumeracy. It’s pretty common.”

“I give up. What’s innumeracy?”

“Innumeracy is the arithmetical equivalent of illiteracy. In this instance, it consists of failing to realize how percentages behave.” A pitching change was taking place, so Pete turned back to me. “An increase in 20% of the tax base will not compensate for a reduction of 20% in each individual’s taxes.   Percentages involve multiplication and division, not addition and subtraction. A gain of 20 dollars will compensate for a loss of 20 dollars, but that’s because you’re dealing with adding and subtracting. It’s not the same with percentages, because the base upon which you figure the percentages varies from calculation to calculation.”

“You may be right, Pete, but how can we tell?”

Pete grabbed a calculator. “Didn’t you say that each faction was out $198,000?”

I checked my figures. “Yeah, that’s the amount.”

Pete punched a few numbers into the calculator. “Call Ryan and see if there were 99,000 taxpayers in the last census. If there were, I’ll show you where the money went.”

I got on the phone to Ryan the next morning. He confirmed that the tax base in the previous census was indeed 99,000. I told Pete that it looked like he had been right, but I wanted to see the numbers to prove it.

Pete got out a piece of paper. “I think you can see where the money went if you simply do a little multiplication. The taxes collected in the previous census were $100 for each of 99,000 individuals, or $9,900,000. An increase of 20% in the population results in 118,800 individuals. If each pays $80 (that’s the 20% reduction from $100), the total taxes collected will be $9,504,000, or $396,000 less than was collected after the previous census. Half of $396,000 is $198,000.”

I was convinced. “There are going to be some awfully red faces down in Linda Vista. I’d like to see the press conference when they finally announce it.” I went back to the guesthouse, called Allen, and filled him in. He was delighted, and said that the check would be in the mail.   As I’ve said before, when Allen says it, he means it. Another advantage of having Allen make the arrangements is that I didn’t have to worry about collecting the fee, which is something I’ve never been very good at.

I wondered exactly how they were going to break the news to the citizens of Linda Vista that they had to pony up another $396,000, but as it was only about $3.34 per taxpayer I didn’t think they’d have too much trouble. Thanks to a combination of Ryan’s frugality and population increase, the tax assessment would still be lower than it was after the previous census, and how many government agencies do you know that actually reduce taxes? I quickly calculated that if they assessed everyone $3.42 they could not only cover the shortage, but Allen’s fee as well. I considered suggesting it to Ryan, but then I thought that Ryan probably wasn’t real interested in hearing from someone who had made him look like a bungler.

My conscience was bothering me, and I don’t like that. I thought about it, and finally came up with a compromise I found acceptable. I went back to the main house.

Pete was watching another baseball game. The Dodgers fouled up an attempted squeeze into an inning‑ending double play. Pete groaned. “It could be a long season,” he sighed.

“It’s early in the year.” I handed him a piece of paper. “Maybe this will console you.”

“What’s this?” He was examining my check for $1,750. “Your rent’s paid up.”

“It’s not for the rent, Pete. It’s your share of my fee.”

“Fee? What fee?”

“That embezzling case in Orange County. It was worth $3,500 to me to come up with the correct answer. I feel you’re entitled to half of it. You crunched the numbers, but I had the contacts and did the legwork.”

Pete looked at the check. “It seems like a lot of money for very little work. Tell you what. I’ll take $250, and credit the rest towards your rent.”

A landlord with a conscience! Maybe I should notify the Guinness Book of Records. “Seems more than fair to me.”

Pete tucked the check in the pocket of his shirt. “Tell me, Freddy, is it always this easy, doing investigations?”

I summoned up a wry laugh. “You’ve got to be kidding. So far, I’ve asked you two questions that just turned out to be right down your alley. I’ve sometimes spent months on a case, and come up dry. That can make the bottom line look pretty sick. What’s it like in your line of work?”

“I don’t really have a line of work. I have this house and some money in the bank. I can rent out the guesthouse and make enough to live on. People know I’m pretty good at certain problems, and sometimes they hire me. If it looks like it might be interesting, I’ll work on it.” He paused. “Of course, if they offer me a ridiculous amount of money, I’ll work on it even if it’s not interesting. Hey, we’re in a recession.”

“I’ll keep that in mind.”   I turned to leave the room. Pete’s voice stopped me.

“Haven’t you forgotten something?”

I turned around. “I give up. What?”

“We had a bet. You owe me five bucks.”

I fished a five out of my wallet and handed it over. He nodded with satisfaction as he stuffed it in the same pocket as the check, and then turned his attention back to the game.

What made you include this particular idea in the book?

JS: The story features one of the most common misunderstandings about percentages.  There are innumerable mistakes made because people assume that percentages work the same way as regular quantities.  But they don’t — if a store lowers the cost of an item by 30% and then by another 20%, the cost of the item hasn’t been lowered by 50% — although many people make the mistake of assuming that it has.  I’m hoping that the story is sufficiently memorable that if a reader is confronted by a 30% discount followed by a 20% discount, they’ll think “Wasn’t there something like that in The Case of the Vanishing Greenbacks?

There are 14 stories in the book, and each features a mathematical point, injected into the story in a similar fashion as the one above.  I think the stories are fun to read, and if someone reads the book and remembers just a few of the points, well, I’ve done a whole lot better than when I was teaching liberal arts math the way it is usually done.

James D. Stein is emeritus professor in the Department of Mathematics at California State University, Long Beach. His books include LA Math, Cosmic Numbers (Basic) and How Math Explains the World (Smithsonian).