#functional-analysis5 posts

May 23, 2026

Summary of the Talk on Stability of Matter and Mathematical Physics in Vienna

What follows is an AI generated ( notegpt.io, found by google ) summary of Rupert’s recent talk at the Erwin Schrödinger International Institute for Mathematics...

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May 19, 2026

Notes on Lewin Ch4: Spectral Theorem and Functional Calculus

1 Multiplication Operators Let $𝐵\subset {ℝ}^{𝑑}$ be Borel, and let $𝜇$ be a locally finite Borel measure on $𝐵$. We set $ℌ={𝐿}^2(𝐵,d𝜇;ℂ)$. Local finiteness implies that...

mathsfunctional-analysisself-adjointnessnotesrough

May 15, 2026

Notes on Lewin Ch3: Self-adjointness Criteria: Rellich, Kato and Friedrichs

Rellich–Kato Let $(𝐴,𝐷(𝐴))$ be a self-adjoint operator and $0\le 𝛼<1$. We say that an operator $𝐵$ defined on $𝐷(𝐴)$ is $𝐴$-bounded with relative bound $𝛼$ if...

mathsfunctional-analysisself-adjointnessnotesrough

May 7, 2026

Notes on Lewin Ch2: Self-adjointness

Let $ℌ$ be a separable Hilbert space over $ℂ$. Graphs Definition: the graph of an operator $(𝐴,𝐷(𝐴))$ is the vector subpsace of $ℌ\times ℌ$ given by...

mathsfunctional-analysisnotesrough

April 24, 2024

Notes on Lewin Appendix

Appendix A: Sobolev Spaces Definition Definition of ${𝑊}^{𝑘,𝑝}$ is given, and the Meyer-Serrin theorem $𝐻=𝑊$ is stated without proof. Sobolev spaces on the interval Considering...

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