6 research outputs found
Spectrum of mixed bi-uniform hypergraphs
A mixed hypergraph is a triple , where is
a set of vertices, and are sets of hyperedges. A
vertex-coloring of is proper if -edges are not totally multicolored and
-edges are not monochromatic. The feasible set of is the set of
all integers, , such that has a proper coloring with colors.
Bujt\'as and Tuza [Graphs and Combinatorics 24 (2008), 1--12] gave a
characterization of feasible sets for mixed hypergraphs with all - and
-edges of the same size , .
In this note, we give a short proof of a complete characterization of all
possible feasible sets for mixed hypergraphs with all -edges of size
and all -edges of size , where . Moreover, we show that
for every sequence , , of natural numbers there
exists such a hypergraph with exactly proper colorings using colors,
, and no proper coloring with more than colors. Choosing
this answers a question of Bujt\'as and Tuza, and generalizes
their result with a shorter proof.Comment: 9 pages, 5 figure
Rainbow Generalizations of Ramsey Theory - A Dynamic Survey
In this work, we collect Ramsey-type results concerning rainbow edge colorings of graphs
Rainbow Generalizations of Ramsey Theory - A Dynamic Survey
In this work, we collect Ramsey-type results concerning rainbow edge colorings of graphs
Rainbow Generalizations of Ramsey Theory - A Dynamic Survey
In this work, we collect Ramsey-type results concerning rainbow edge colorings of graphs