2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/224561We analyze the trade-off between the amounts of information obtainable on complementary properties of a qubit state by simultaneous measurements. We consider a "state discrimination" scenario wherein the same measurements are repeated, but the input states must be guessed in every run. We find a general complementarity relation for path-phase guesses by any generalized measurements in this scenario. The counterpart of this input-output mutual information (MI) reveals a hitherto unknown aspect of complementarity.3 figuresQuantum Physicstext