# You're reading: Black Mathematician Month

### Ditching the fifth axiom (video)

Watch geometer/topologist Caleb Ashley explain the parallel postulate on Numberphile.

### Stirling’s numbers in a nutshell

This is a guest post by researcher Audace Dossou-Olory of Stellenbosch University, South Africa.

In assignment problems, one wants to find an optimal and efficient way to assign objects of a given set to objects of another given set. An assignment can be regarded as a bijective map $\pi$ between two finite sets $E$ and $F$ of $n\geq 1$ elements. By identifying the sets $E$ and $F$ with $\{1,2,\ldots, n\}$, we can represent an assignment by a permutation.

### A new aspect of mathematics

This is a guest post written by David Nkansah, a mathematics student at the University of Glasgow.

Around the fourth century BC, the term ‘Mathematics’ was defined by Aristotle as the “science of quantity”. It’s my own experience as a young mathematician to say this definition, although correct in its own right, poses a problem for those who do not truly know what mathematics is. It fails to highlight the true creativity of the subject.

Human inspiration and imagination are essential ingredients in mathematics. Regarding creativity, one could say, with merit, that in a sense mathematics is an art. Before proceeding to outline similarities between sketching mathematical proofs and painting on a canvas, it is important to know what fundamental premises mathematical proofs are built on.

### Binary, with Anne-Marie Imafidon (video)

Watch mathematician and entrepreneur Anne-Marie Imafidon MBE explain binary numbers. Anne-Marie studied for an MSc in mathematics at Oxford University, and founded the social enterprise Stemettes to encourage more women and girls into STEM careers.

### Mathematical modelling of Facebook use (video)

Watch mathematician and data scientist Jonny explain mathematical modelling of networks.

### Circular reasoning on Catalan numbers

This is a guest post by researcher Audace Dossou-Olory of Stellenbosch University, South Africa.

Consider the following question: How many ways are there to connect $2n$ points on a circle so that each point is connected to exactly one other point?