Time: 2019-03-21 19：00-20：30

Venue: Room 201 Lecture Hall

abstract：An exact phase-retrievable frame {f_{i}}_{i}^{N} for an n-dimensional Hilbert space is a phase-retrievable frame that fails to be phase-retrievable if any one element is removed from the frame. Such a frame could have different lengths. We shall prove that for the real Hilbert space case, exact phase-retrievable frame of length N exists for every 2n-1\leq N\leq n(n+1)/2. For arbitrary frames we introduce the concept of redundancy with respect to its phase-retrievability and the concept of frames with exact PR-redundancy.