Factorizations of contractions

Regular Factorizations of Contractions

Equivalent conditions are given for the regularity of a factorization of a contraction, two of which exhibit immediately the duality property of this notion. The concept of regular factorization of contractions of Hubert spaces1 was introduced in [1] by the authors in connection with their investigations on the invariant subspace problem; cf. [2, §VIL3]. Let A0 be a contraction of a Hubert spac...

Holey factorizations

Holey factorizations of Kv1,v2,...,vn are a basic building block in the construction of Room frames. In this paper we give some necessary conditions for the existence of holey factorizations and give a complete enumeration for nonisomorphic sets of orthogonal holey factorizations of several special types.

Free Factorizations

Embedding Factorizations for 3-Uniform Hypergraphs II: $r$-Factorizations into $s$-Factorizations

Motivated by a 40-year-old problem due to Peter Cameron on extending partial parallelisms, we provide necessary and sufficient conditions under which one can extend an r-factorization of a complete 3-uniform hypergraph on m vertices, K3 m, to an s-factorization of K3 n. This generalizes an existing result of Baranyai and Brouwer–where they proved it for the case r = s = 1.

Localization of Matrix Factorizations

Matrices with off-diagonal decay appear in a variety of fields in mathematics and in numerous applications, such as signal processing, statistics, communications engineering, condensed matter physics, and quantum chemistry. Numerical algorithms dealing with such matrices often take advantage (implicitly or explicitly) of the empirical observation that this off-diagonal decay property seems to b...