linear operators 50 Hilbert spaces 12 Banach spaces 11 operator theory 10 functional analysis 8 approximation 4 linear and multilinear algebra 4 more ... matrix algebra 4 positive operators 4 vector spaces 4 evolution equations 3 function spaces 3 quantum mechanics 3 semigroups 3 weight functions 3 Boolean algebra 2 Jordan structures 2 analytical function 2 differential operators 2 function of several complex variables 2 integral operators 2 numerical methods in linear algebra 2 manifolds 2 Cauchyův problém 1 Feynman path integral 1 Fredholm equations 1 Hilbert algebras 1 Minkowski geometry 1 Abel groups 1 algebra 1 less ...