🌐EnglishEnglishDeutschFrançaisItalianoРусский中文日本語EntityQ4454958· pop 5· linked from 451 articlesMin-max theoremvariational characterization of eigenvalues of compact Hermitian operators on Hilbert spacesAvailable in 5 languagesFrançaisDeutschРусскийUkrainianvia Wikidata sitelinks · CC0ConnectionsBanach algebraEntityspectrumEntityCategoriesOperator theorySpectral theoryTheorems in functional analysis