You are cordially invited to the M.S. Thesis Defense Presentation
“Thomason’s Homotopy Colimit Theorem and Cohomology of Categories”
Mehmet Kırtışoğlu, M.S. Student in Mathematics
Abstract: In 1978, R.W. Thomason proves that given a functor F from a small category C to the category of small categories, there is a homotopy equivalence from the homotopy colimit of the nerve of F over C and the nerve of Grothendieck construction over F. We prove that Grothendieck construction is a precofibred category over the canonical functor from the Grothendieck construction to C. We also prove that for any functor φ : D → C between arbitrary small categories, there is a homotopy equivalence λ : hocolim_C N(φ/c) → N(D) from the homotopy colimit of nerves of left comma categories to nerve of D. We show that these two together proves Thomason’s homotopy colimit theorem from a conceptual point of view.
We further investigate how our conceptual approximation for the proof of Thomason’s homotopy colimit theorem becomes useful for the cohomology version of Thomason’s theorem which was proven by A. M. Cegarra in 2020.
Advisor: Prof. Dr. Ergün YALÇIN
Date: Tuesday, July 2, 2024
Time: 14:00
Place: SA 141 – Mathematics Seminar Room