2 problems

Neumann–Lara's acyclic 2-coloring conjecture for planar digraphs
Neumann–Lara's conjecture. Every planar digraph of digirth at least $3$ can be vertex-partitioned into two acyclic sets.
openacyclic-coloring planar-digraphs
0 responses
03
McDiarmid–Mohar conjecture on acyclic chromatic number of oriented graphs
McDiarmid–Mohar conjecture. Every oriented graph $D$ satisfies
openacyclic-coloring digraphs oriented-graphs
0 responses
07

Neumann–Lara's acyclic 2-coloring conjecture for planar digraphs