Hello all, The next MaPSS talk of this semester will be at 17:00 on Monday 8th April in Carslaw 535. It’s a great opportunity to meet fellow postgrads, listen to an interesting talk, and of course get some free pizza! ************************************************************************************** Speaker: Carol Badre Title: An Introduction to Bass-Serre Theory Abstract: One of the most fundamental parts of geometric group theory is Bass-Serre theory. Bass-Serre theory was introduced by Serre (and developed further by Bass) in the 1970’s in order to understand how groups act on simplicial trees. This theory allows for the extraction of information of the structure of a group from its action on a tree, characterising free groups, amalgamated products and their generalisations as groups acting on simplicial trees. Bass-Serre theory has inspired developments in the accessibility of groups, JSJ decomposition of finitely presented groups, lattices in automorphism groups of trees, as well as results in the world of CAT(0)-cube complexes and R-trees. Today I will give a gentle introduction to Bass-Serre theory. ************************************************************************************** See you there! Details can also be found on the school’s new Postgraduate Society website: http://www.maths.usyd.edu.au/u/MaPS/mapss.2019.html Cheers, Eric