Degree sequence condition for Hamiltonicity in tough graphs

Generalizing both Dirac's condition and Ore's condition for Hamilton cycles, Chvatal in 1972 established a degree sequence condition for the existence of a Hamilton cycle in a graph. Hoang in 1995 generalized Chvatal's degree sequence condition for 1-tough graphs and conjectured a t-tough analogue for any positive integer t at least 1. Hoang in the same paper verified his conjecture for t at most 3 and recently Hoang and Robin arXiv:2303.03479v2 verified the conjecture for t = 4. In this paper, we confirm the conjecture for all t at least 4.