Mirror symmetry on K3 surfaces as a hyperkaehler rotation
  We show that under the hypotheses of Strominger, Yau and Zaslow's paper, a mirror partner of a K3 surface $X$ with a fibration in special Lagrangian tori can be obtained by rotating the complex structure of $X$ within its hyperk\"ahler family of complex structures. The same hypotheses force the B-field to vanish. 
U. Bruzzo (SISSA, Trieste), G. Sanguinetti (University of Genova,   Italy)