Algebraic Graph Theory Seminar - Peter Dukes

Monday, November 29, 2021 11:30 am - 11:30 am EST (GMT -05:00)

Title: Fractional decompositions and Latin square completion

Speaker: Peter Dukes
Affiliation: University of Victoria
Zoom: Contact Soffia Arnadottir

Abstract:

It was shown recently by Delcourt and Postle that any sufficiently large graph $G$ of order $n$ with minimum degree at least $0.827n$ has a fractional triangle decomposition, i.e. an assignment of weights to the triangles in $G$ such that for every edge $e$, the total of all weights of triangles containing $e$ is exactly one.

This talk will consider the same problem in the $3$-partite setting.  Using algebraic methods, we establish a minimum degree threshold for balanced $3$-partite graphs to admit a fractional triangle decomposition.  Invoking the absorber work of Barber, K\"uhn, Lo, Osthus and Taylor, our threshold improves the status of the completion problem for sparse partial Latin squares of large order.

This is based on joint work with Flora Bowditch.