Abstract
We analyze the P 3 -geodetic number, the P 3 -hull number and the P 3 -Carathéodory number for tree-cographs, and these parameters for P 4 -reducible graphs. We also show that the P 3 hull number is polynomial for permutation graphs. Moreover, we give monadic second-order formulas for the P 3 -hull and P 3 -Carathéodory numbers in general, thus showing that these parameters are polynomial for graphs of bounded rankwidth or treewidth.