What is a z-score?

A z-score is the number of standard deviations from a mean data point. "x minus mu over sigma" is the typical formula for a z-score.

Python Programmers and Physics

Python programmers who like physics read Physics World.

Pi calculated to 31 trillion digits

A Google employee from Japan has calculated pi to 31 trillion digits. The calculation took 25 virtual machines 121 days to complete. The value pi appears all over mathematics, from the area of a circle to the evaluation of the Riemann zeta function.

What did Nikolay Krasovsky Study?

Nikolay Krasovsky, born in Yekaterinburg (on the Iset River), worked in the mathematical theory of control, dynamical systems and differential games.

A Lookback at 17th Century Maths

A very good "lookback" at 17th Century maths can be found on the following website. This includes Edmonton-born Brook Taylor's treatise: "Methodus Incrementorum Directa & Inversa". Taylor was famed for the Taylor series and Taylor's theorem. John Napier's treatise on logarithms is also presented in translated form: "Mirifici Logarithmorum Canonis Descriptio".

Latin is one of the "hazards" of reading 17th Century maths. As a taster, Mirifici (above) is the plural of Mirificus (wonderful, miraculous). Canonis is the genitive of canon (referring to a catalog of sacred writings). Descriptio means simply description.

As well as discovering logarithms, John Napier was also known for inventing the so-called "Napiers Bones" which was a calculating device for multiples and quotients. It was based on lattice multiplication.

Bifurcation Theory for PyCryptonistas

What is bifurcation theory? An abstract definition is possible, but the most common usage is in dynamical systems, when a small change to parameters creates a major change to the "topology" of a solution (typically of a family of differential equations). It is informally part of the "qualitative" theory of differential equations.

Revisiting The Legendary Doob

Pick up a book on stochastic processes and you will invariably see references to the legendary Doob.

Joseph Doob was an American mathematician who developed the theory of martingales.

He was born in Cincinnati, Ohio and the family later moved to New York City.

He studied at Harvard, where is advisor as Joseph Walsh, known for the Walsh function.