Seminar usually held on Thursdays at 11:30 am (Israel time) in Amado room 814. Exceptions will be marked in red.
30 March at 11:30
Bogdan Chornomaz (Technion)
Title: Bounds between the time complexity of the word problem of a group and the Dehn function of its Higman embedding.
Abstract: I will talk about a recent result of Frank Wagner and myself, where we prove that S-machines can emulate Turing machines in quasilinear time. This implies, for example, that a group G whose word problem can be solved in time T(n) can be isometrically embedded into a finitely presented group H such that the Dehn function of H is at most $n^2 T(n^2)^{2+\epsilon}$, and the Dehn function of G in H is at most $T(n)^{2+\epsilon}$, improving the bounds of Sapir, Birget, Rips, and Ol'shanskii ($n^2 T(n^2)^4$ and $T(n)^4$ respectively).
20 April at 11:30
Arie Levit (TAU)
24 April (Monday) at 11:30
Igor Zelenko (Texas A&M)
04 May at 11:30
Yvon Verberne (U of Toronto)