## Girls’ Angle Bulletin, Volume 5, Number 3

The latest issue of the Bulletin covers a wide variety of mathematics from combinatorics to topology. In the print version, there’s also an interview with MIT Ph.D. biostatistician Dana Pascovici who works at the Australian Proteome Analysis Facility in Sydney.

A Seifert surface made using the program SeifertView.

Earlier this month, Dr. Meike Akveld, a knot theorist who works at ETH Zürich, visited the club and gave a wonderful presentation on knots. Many members have become quite intrigued with knots, and so in this issue, we included pictures of some Seifert surfaces, which are oriented surfaces whose boundaries are knots or links. These images were made using SeifertView, a free program downloadable from the internet written by Jarke J. van Wijk of the Technische Universiteit Eindhoven.

In Anna’s Math Journal, Anna continues her exploration of certain polynomial sums. There’s a lot there to explore! Anna’s Math Journal attempts to present mathematics in its “workshop” form. Nearly all published math literature presents math in a polished, gem-like state. All the errors and confusion are swept away and that could give the misleading impression that mathematicians are people who make one keen observation after another. The world receives Andrew Wiles’s brilliant proof of Fermat’s Last Theorem, but doesn’t see the years of toil and abandoned computations that led to it. We hope readers will latch on to Anna’s enthusiasm and begin carrying out explorations of their own and perhaps answer some of the questions that Anna has been thinking about.

In our other regular columns, Coach Barb explains a nice way of understanding why, when you multiply fractions, you can just take the product of the numerators and divide that by the product of the denominators. Cammie Smith Barnes hopes you never err again when you have to compose two functions. And Katherine Sanden discusses the rigidity of triangles and some interesting mathematical implications of this rigidity.

Also inside, MIT math major Shravas Rao introduces permutations and combinations in a succinct article which assumes no prior knowledge beyond arithmetic. And there’s more…on Ceva’s theorem, Pappus’s centroid theorems, a fraction worksheet… hope you enjoy it!