MathDB
Functional value at x is taken at points converging to x

Source: Miklós Schweitzer 2017, problem 9

January 13, 2018
normed vector spaceFunctional Analysisanalysiscollege contestsadvanced fields

Problem Statement

Let NN be a normed linear space with a dense linear subspace MM. Prove that if L1,,LmL_1,\ldots,L_m are continuous linear functionals on NN, then for all xNx\in N there exists a sequence (yn)(y_n) in MM converging to xx satisfying Lj(yn)=Lj(x)L_j(y_n)=L_j(x) for all j=1,,mj=1,\ldots,m and nNn\in \mathbb{N}.