Let H be a seperable Hilbert space and M a countable dense subset of H.

Show that H contains a total orthonormal sequence which can be obtained from M by the Gram-Schmidt process. (Itwasntme)

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- May 31st 2009, 01:42 PMfrater_cpGram-Schmidt Process
Let H be a seperable Hilbert space and M a countable dense subset of H.

Show that H contains a total orthonormal sequence which can be obtained from M by the Gram-Schmidt process. (Itwasntme) - May 31st 2009, 02:15 PMJose27
Let be your countabl dense subset of , and the sequence obtained by applying the Gram-Schmidt process to . Then let and be two elements in and then applying G-S to the first vectors we conclude that . So is an orthonormal set.

Now, without loss of generality, we may assume that is linearly independent, and since is contained in for every we have . Let , since is linearly independent (actually orthogonal) and we have (remember that all basis for a vector space have the same cardinality) that is a basis for and so . And you're finished