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(2001 / vol.4 / no.1)
Weights of Idempotent Matrices
L. B. Beasley, Sang-Gu Lee, Se-Won Park
Pages. 95-100



We investigate the possible number of nonzero entries in binary $(0,1)$ and real $(0,1,-1)$ idempotent matrices.



1. Preliminaries
2. Main results



idempotent matrix, weights, sign pattern matrix



15A04, 15A21, 15A30