EntityQ1472120· pop 7· linked from 9 articlesHellinger–Toeplitz theoremSign in to savetheoremConnectionsinner product spaceEntityself-adjoint operatorEntitymathematicsEntityInternational Standard Book NumberEntityProvidenceEntityHilbert spaceEntityfunctional analysisEntityRiemann hypothesisEntityeigenvectors and eigenvaluesEntitycalculus of variationsEntityBanach spaceEntitydense setEntityquantum harmonic oscillatorEntitynormed vector spaceEntityAmerican Mathematical SocietyEntitydual spaceEntitymathematical formulation of quantum mechanicsEntitydistributionEntityLp spaceEntitytopological vector spaceEntityCategoriesHilbert spacesTheorems in functional analysis