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2 votes
1 answer
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Decomposition of the spectrum of an unbounded opeator [closed]

The Wikipedia article on spectral decomposition, see here https://en.wikipedia.org/wiki/Self-adjoint_operator says the following: A self-adjoint operator A on $H$ has pure point spectrum if and ...
Dale Wintermann's user avatar
2 votes
1 answer
238 views

Why is index unchanged after applying functional calculus?

Suppose $D$ is the Dirac operator on a closed spin manifold $M$, with spinors $S$. One can take the functional calculus of $D$ with respect to the continuous function $f:\mathbb{R}\rightarrow\mathbb{R}...
geometricK's user avatar
  • 1,903
11 votes
2 answers
2k views

How "generalized eigenvalues" combine into producing the spectral measure?

Hi... I am wondering how 'eigenvalues' that don't lie in my Hilbert space combine into producing the spectral measure. I study probability and I am quite ignorant in the field of spectral analysis of ...
Reda's user avatar
  • 333
5 votes
1 answer
807 views

Self-adjoint extension of locally defined differential operators

The following is well known. Given a symmetric differential operator, like $\partial_x^2$, defined on smooth functions of compact support on $\mathbb{R}$, $C_0^\infty(\mathbb{R})$, one can count the ...
Igor Khavkine's user avatar