Typical ranks in symmetric matrix completion

We study the problem of low-rank matrix completion for symmetric matrices. The minimum rank a generic partially specified depends only on location entries, and not their values, if complex entries are allowed. When required to be real, this is no longer case possible ranks called typical ranks. give combinatorial description patterns n×n matrices that have n as rank. Moreover, we describe exactly when such partial minimally completable n. also characterize with low maximal