Math Problem Statement

Let X be an inner product space and let P: X -> X and Q: X -> X be any two projections. If R(P) ⊆ R(Q), then show that R(P) = R(Q) implies P = Q. Let H be a Hilbert space and let M be a non-empty convex subset of H. Let (x_n) be a sequence in M such that ||x_n|| -> α where α = inf ||x||. Then show that x ∈ M.

Solution

The image you uploaded contains mathematical problems. Let's go over them:

  1. The first part involves projections in an inner product space XX. It asks to show that if PP and QQ are two projections, then R(P)R(Q)R(P) \subseteq R(Q) implies P=QP = Q.

  2. The second part concerns a Hilbert space HH, with a non-empty convex subset MM. It asks to prove that for a sequence (xn)(x_n) in MM, where xn\| x_n \| approaches a value α\alpha, and α=infx\alpha = \inf \| x \|, we need to prove a certain result.

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Math Problem Analysis

Mathematical Concepts

Inner Product Spaces
Projections
Hilbert Spaces
Sequences
Convex Sets

Formulas

||x_n|| -> α
α = inf ||x||

Theorems

Projections theorem
Convexity in Hilbert Spaces

Suitable Grade Level

Undergraduate (Mathematics or Functional Analysis)