WFunctional analysis
WBounded set
WBred vector
WCommutative property
WConvolution
WDiscretization
WEigenfunction
WExposed point
WExtreme point
WGram–Schmidt process
WHilbert space
WInvariant subspace problem
WLinear subspace
WMollifier
WMonotonic function
WOrdered vector space
WPerturbation theory
WPolarization identity
WProjection (linear algebra)
WSingular value decomposition
WSupporting hyperplane
WUniform norm
WVariance function
WWavelet transform