## Still A Brilliant Idea

* An apology and correction *

Cynthia Dwork, Frank McSherry, Kobbi Nissim, and Adam Smith are the inventors of differential privacy, as formulated in their 2006 paper “Calibrating Noise to Sensitivity in Private Data Analysis,” in the proceedings of the 2006 Theory of Cryptography Conference.

Today Ken and I want to talk about differential privacy again.

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## Cynthia Dwork and a Brilliant Idea

* Differential Privacy *

Taekwondo source |

Cynthia Dwork is a computer scientist who is a Distinguished Scientist at Microsoft Research. She has done great work in many areas of theory, including security and privacy.

Today Ken and I wish to talk about the notion of differential privacy and Dwork’s untiring advocacy of it.

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## Where Hard Meets Easy

* Some hard to compute functions are easy modulo a number *

Georgia Tech source |

Joseph Ford was a physicist at Georgia Tech. He earned his undergrad degree here in 1952, and after earning his PhD at Johns Hopkins, went to work for two years at Union Carbide in Niagara Falls before joining the University of Miami and then coming back to Tech. He was possibly lured back into academia by considering a paradox studied by Enrico Fermi, John Pasta, Stanislaw Ulam, and Mary Tsingou in the mid-1950s. The paradox is that periodic rather than ergodic motion can often result in complicated systems.

Today we wish to present a simple observation about hard-to-compute functions.

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## Why is Congruence Hard to Learn?

* Gears and rings… *

Flickr source: |

Denys Fisher was a British engineer and maker of board games and other toys. In 1965 he invented the Spirograph toy. Some speculate that he was influenced by the designs of the artist, composer, and film animator John Whitney, whose opening sequence for Alfred Hitchcock’s 1958 film “Vertigo” is considered the first use of computer graphics in cinema. The Spirograph toy involves drawing with a pen guided by a gear with *m* teeth going around inside a ring or around a track or other gear with *x* teeth. The kind of design you get depends on how *x* relates to *m*.

Today Ken and I want to talk about a basic notion of mathematics and theory that is simple to define, very useful, and yet seems to be tough for some students to get.

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## A Computer Chess Analysis Interchange Format

* File formats are like watching paint dry… *

Source: Chess-programming wiki on Edwards’s “Spector” program. |

Steven Edwards is an American computer scientist and chess programmer. Two decades ago he spearheaded the development and adoption of three standards for communicating chess games and their moves.

Today Ken wishes to present a proposed new format for representing computer analysis of chess games and positions.

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## Forgetting Results

* Rejoining many who have forgotten or overlooked results *

St. Andrews Mac Tutor biographies source |

Henry Smith was a mathematician of the 19th century who worked mainly in number theory. He especially did important work on the representation of numbers by various quadratic forms. We have discussed how even in something seemingly settled, like Joseph Lagrange’s theorem that every natural number is representable as a sum of four squares, new questions are always around—especially when one considers complexity.

Today Ken and I want to discuss a private slip of forgetfulness, and how often others may have done the same.

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## There Are Many Primes

* Various senses of ‘many’ from proofs of the infinitude of primes *

2008 Bowen Lectures source |

Hillel Furstenberg is entering his 50th years as a professor of mathematics at Hebrew University in Jerusalem. He shared the 2006-07 Wolf Prize with Stephen Smale. He has shown many connections between analysis and combinatorics. One was showing how ergodic theory can prove Endre Szemerédi’s theorem that every positive-density subset of the integers includes arbitrarily-long arithmetic progressions . This led to a new multidimensional formulation with Yitzhak Katznelson, and the two later proved positive-density versions of the Hales-Jewett theorem.

Today Ken and I wish to discuss proofs of the infinitude of primes, and what they begin to say about analysis and combinatorics.

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