#scheduling

Seven speakers — Turing (T), Lovelace (L), Bohr (B), Curie (C), Socrates (S), Pythagoras (P) and Newton (N) — get one of four slots, 1–4 pm. Turing must take 1 pm. These pairs may not share a slot: every pair within {B, C, N}, within {L, P, N}, within {T, L, N}, and the pairs S–P, L–C and C–P. Assign in the order T, L, B, C, S, P, N, always trying the earliest slot, with depth-first search plus forward checking. Who shares the 1 pm slot with Turing in the schedule found?