Recognition of probe H-free graphs and identification of probes
Develop polynomial-time recognition algorithms for probe H-free graphs and determine the distinction between probes and non-probes for general graphs H.
References
However, for most graphs~$H$, the recognition of probe $H$-free graphs and the distinction between probes and non-probes are open problems.
— Colouring Probe $H$-Free Graphs
(2505.20784 - Paulusma et al., 27 May 2025) in Section 1, Introduction, subparagraph “Our Focus”