On a Conjecture for a Hypergraph Edge Coloring Problem

06/11/2020
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by   Wieslaw Kubiak, et al.
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Let H =(β„³βˆͺπ’₯ ,E βˆͺβ„°) be a hypergraph with two hypervertices 𝒒_1 and 𝒒_2 where β„³ =𝒒_1βˆͺ𝒒_2 and 𝒒_1βˆ©π’’_2 =βˆ…. An edge {h ,j}∈ E in a bi-partite multigraph graph (β„³βˆͺπ’₯ ,E) has an integer multiplicity b_j h, and a hyperedge {𝒒_β„“ ,j}βˆˆβ„°, β„“=1,2, has an integer multiplicity a_j β„“. It has been conjectured in [5] that Ο‡' (H) =βŒˆΟ‡' _f (H)βŒ‰, where Ο‡' (H) and Ο‡' _f (H) are the edge chromatic number of H and the fractional edge chromatic number of H respectively. Motivation to study this hyperedge coloring conjecture comes from the University timetabling, and open shop scheduling with multiprocessors. We prove this conjecture in this paper.

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