We consider the algebra of Hecke correspondences (elementary transformations
at a single point) acting on the algebraic K-theory groups of the moduli spaces
of stable sheaves on a smooth projective surface S. We derive quadratic
relations between the Hecke correspondences, and compare the algebra they
generate with the Ding-Iohara-Miki algebra (at a suitable specialization of
parameters), as well as with a generalized shuffle algebra