Model Checking Disjoint-Paths Logic on Topological-Minor-Free Graph Classes

Disjoint-paths logic, denoted FO+ DP, extends first-order logic (FO) with atomic predicates dpk[(x1, y1), …, (xk, yk)], expressing the existence of internally vertex-disjoint paths between xi and yi, for 1 ≤ i ≤ k. We prove that for every graph class excluding some fixed graph as a topological minor, the model checking problem for FO+ DP is fixed-parameter tractable. This extends the model checking algorithm of Golovach et al. [SODA 2023] for FO+ DP for minor-closed graph classes. It also essentially settles the question of tractable model checking for this logic on subgraph-closed classes, since the problem is hard on subgraph-closed classes not excluding a topological minor (assuming a further mild condition on efficiency of encoding).