Does anyone know anything about M. Meyniel? According to zbMath, he published precisely one mathematics paper, in which he gave a sufficient condition for hamiltonicity of digraphs:

"Une condition suffisante d'existence d'un circuit hamiltonien dans un graphe oriente" (

JCTB14(1973), 137–147).

In that paper, he was listed with an address but no affiliation. The address was 13, rue Poirier de Narçay, Paris 14ᵉ, which appears to be an apartment above a game store for what it is worth.

I assume that M. Meyniel is distinct from Henri Meyniel of Meyniel graphs and Meyniel's conjecture. That said, the paper "Sufficient conditions for a digraph to be Hamiltonian" (*J. Graph Th.* **22** (1996) 181–187) is dedicated to the memory of Henri Meyniel and lists Henri Meyniel as the author of M. Meyniel's paper (item [15] in the bibliography).

I assume that M. Meyniel is distinct from Henri Meyniel: Why exactly do you assume that, given that the only available evidence suggests the contrary? $\endgroup$3more comments