RT Journal Article T1 Grothendieck's theorem for absolutely summing multilinear operators is optimal A1 Pellegrino, Daniel A1 Seoane Sepúlveda, Juan Benigno AB Grothendieck's theorem asserts that every continuous linear operator from ℓ1 to ℓ2 is absolutely (1;1)-summing. In this note we prove that the optimal constant gm so that every continuous m-linear operator from ℓ1×⋯×ℓ1 to ℓ2 is absolutely (gm;1)-summing is 2m+1. We also show that if gm<2m+1 there is c dimensional linear space composed by continuous non absolutely (gm;1)-summing m-linear operators from ℓ1×⋯×ℓ1 to ℓ2. In particular, our result solves (in the positive) a conjecture posed by A.T. Bernardino in 2011. PB Taylor & Francis SN 0308-1087 YR 2015 FD 2015-03 LK https://hdl.handle.net/20.500.14352/23017 UL https://hdl.handle.net/20.500.14352/23017 LA eng DS Docta Complutense RD 12 may 2025