Mittagsseminar (in cooperation with A. Steger, D. Steurer and B. Sudakov)

Date and Time: Tuesday, November 20, 2007, 12:15 pm

Duration: This information is not available in the database

Location: OAT S15/S16/S17

Speaker: Dan Hefetz

Antimagic graphs via the Combinatorial Nullstellensatz

An antimagic labeling of a graph with n vertices and m edges is a bijection from the set of edges to the integers 1,...,m such that all n vertex sums are pairwise distinct, where a vertex sum is the sum of labels of all edges incident with that vertex. A graph is called antimagic if it admits an antimagic labeling. In 1990, it was conjectured by Ringel that any simple connected graph, other than K_2, is antimagic. Despite some efforts (and some partial results) in recent years, this conjecture is still open. In this talk I will sketch a proof of one partial result; namely, any graph on n = 3^k vertices which admits a triangle factor is antimagic. The main tool that will be used is a powerful algebraic method called the Combinatorial Nullstellensatz.

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