Generalized orthogonal projections and shorted operators
Gustavo Corach, Alejandra Maestripieri, Demetrio Stojanoff · 2001
Dedicated to the memory of our friend Chicho Guadalupe Abstract. Let H be a Hilbert space, L(H) the algebra of all bounded linear operators on H and 〈 , 〉A: H×H → C the bounded sesquilinear form induced by a selfadjoint A ∈ L(H), 〈ξ, η〉A = 〈Aξ, η〉, ξ, η ∈ H. Given T ∈ L(H), T is A-selfadjoint if AT = T ∗A. If S ⊆ H is a closed subspace, we study the set of A-selfadjoint projections onto S,