D-Brane Probes and Mirror Symmetry

We study the effect of mirror symmetry for K3 surfaces on D-brane probe physics. The case of elliptically fibered K3 surfaces is considered in detail. In many cases, mirror can transform a singular fiber of Kodaira's type ADE into sets of singular fibers of type I_1 (II) with equal total Euler number, but vanishing contribution to the Picard number of the mirror surface. This provides a geometric model of quantum splitting phenomena. Mirror for three dimensional gauge theories, interchanging Fayet-Iliopoulos and mass terms, is also briefly discussed.