2019
Том 71
№ 11

# Feshchenko I. S.

Articles: 1
Article (Russian)

### On closeness of the sum of n subspaces of a Hilbert space

Ukr. Mat. Zh. - 2011. - 63, № 10. - pp. 1381-1425

We give necessary and sufficient conditions for the sum of subspaces $H_1,..., H_n,, \quad n \geq 2,$ of a Hilbert space $H$ to be a subspace and present various properties of $n$-tuples of subspaces with closed sum.