Research problems (Q5899801)

Following problems are coined: Problem 128 (J. R. Griggs and D. B. West): For interval intersection representations of graphs an interval number of a graph is defined. It is asked for the maximum value of it in terms of the number of edges. Problem 129 (V. Petrović): About the partition of 2k-element, integer sets into two k-element sets with the property that the sum of k-1 of the one is not an element of the other.