“…In this paper, we consider (1.1) without angular cutoff by using the triple norm, introduced by Alexandre, Morimoto, Ukai, Xu, and Yang (AMUXY in what follows) [4,7]. The triple norm was originally adopted to discuss the equation in L ∞ t (0, ∞; H k l (R 6 x,v )) for suitable l, k ∈ N. We combine both ideas [13] and [7](see also [5,6,8]) to discuss the Cauchy problem without angular cutoff. For this purpose, we later introduce a Chemin-Lerner type triple norm, which enables us to take full advantage of the two ideas.…”