COMPOSITIO MATHEMATICA vol. 151, no. 2, pp. 377 - 396
CAMBRIDGE UNIV PRESS
SCI; SCIE; SCOPUS
We prove that, for simple modules M and N over a quantum affine algebra, their tensor product M circle times N has a simple head and a simple socle if M circle times M is simple. A similar result is proved for the convolution product of simple modules over quiver Hecke algebras.