EN
For $(P_{k})$ being Rademacher, Fermion or q-Gaussian (-1 ≤ q ≤ 0) operators, we find the optimal constants $C_{2n}$, n∈ ℕ, in the inequality
$∥∑_{k=1}^{N} A_k ⊗ P_k∥_{2n} ≤ [C_{2n}]^{1/2n} max {∥(∑_{k=1}^{N} A*_k A_k}^{1/2}∥_{L_{2n}}, ∥(∑_{k=1}^{N} A_k A*_k}^{1/2}∥_{L_{2n}}}$,
valid for all finite sequences of operators $(A_{k})$ in the non-commutative $L_{2n}$ space related to a semifinite von Neumann algebra with trace. In particular, $C_{2n} = (2nr-1)!!$ for the Rademacher and Fermion sequences.