Hoàng's conjecture. Let n≥3n\ge 3n≥3 and t≥1t\ge 1t≥1 be integers. If GGG is ttt-tough and, for every i<n2i<\frac n2i<2n, di≤id_i\le idi≤i implies dn−i+t≥n−id_{n-i+t}\ge n-idn−i+t≥n−i, then GGG is Hamiltonian.
