15 citations · 57 across the 24 of their papers we have counts for
4 papers · 1 filter
Planar graphs have exponentially many 3-arboricities
Ararat Harutyunyan, Bojan Mohar
It is well-known that every planar or projective planar graph can be 3-colored so that each color class induces a forest. This bound is sharp. In this paper, we show that there are…
Two results on the digraph chromatic number
Ararat Harutyunyan, Bojan Mohar
It is known (Bollobás (1978); Kostochka and Mazurova (1977)) that there exist graphs of maximum degree and of arbitrarily large girth whose chromatic number is at least $c Δ/ \…
Strengthened Brooks Theorem for digraphs of girth three
Ararat Harutyunyan, Bojan Mohar
Brooks' Theorem states that a connected graph of maximum degree has chromatic number at most , unless is an odd cycle or a complete graph. A result of Johansson (199…
Uniquely D-colourable digraphs with large girth
Ararat Harutyunyan, P. Mark Kayll, Bojan Mohar +1
Let C and D be digraphs. A mapping is a C-colouring if for every arc of D, either is an arc of C or , and the preimage of every vertex o…