Arazy's conjecture concerning Schur multipliers: revisited and resolved

Let S^ r denote the Schatten--von Neumann class and let S_Ψf,λ be the Schur--Hadamard multiplier whose symbol is the divided-difference matrix of f along $λ$. Let 0<α,r<∞, let f∈ C¹([-1,1]) satisfy $f(0)=0$, |f'(t)| |t|^α, and let λ∈ʳ be real with \|λ\|^∞≤1. We determine the pairs $0