Componentwise and Cartesian decompositions of linear relations
Seppo Hassi, Hendrik S. V. de Snoo, Franciszek Hugon Szafraniec · Dissertationes Mathematicae · 2009
Let $A$ be a, not necessarily closed, linear relation in a Hilbert space $\got H$ with a multivalued part $\mathop{\rm mul} A$. An operator $B$ in $\got H$ with $\mathop{\rm ran} B\perp\mathop{\rm mul} A^{**}$ is said to be an operator part of $A$ when $A