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A mixed hypergraph is a pair H=(V,E∪A), where V is the vertex set and E (A) the edge (the co-edge) set of H. A legal colouring of H gives the same (different) colour(s) to at least two vertices of any co-edge (of any edge). The upper chromatic number of H is the maximum number χ ̄(H) of colours that can be used in a legal colouring. After giving a general upper bound to χ ̄(H), we here consider...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.