87 citations · 660 across the 43 of their papers we have counts for
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A note on infinite extreme correlation matrices
J. Kiukas, J. -P. Pellonpää
We give a characterization for the extreme points of the convex set of correlation matrices with a countable index set. A Hermitian matrix is called a correlation matrix if it is p…
On infinite matrices, Schur products, and operator measures
J. Kiukas, P. Lahti, J. -P. Pellonpää
Measures with values in the set of sesquilinear forms on a subspace of a Hilbert space are of interest in quantum mechanics, since they can be interpreted as observables with only…
Notes on phase space quantization
J. Kiukas, P. Lahti, K. Ylinen
We consider questions related to a quantization scheme in which a classical variable f:Ω\to R on a phase space Ωis associated with a semispectral measure E^f, such that the moment…
Covariant observables on a nonunimodular group
J. Kiukas
It is shown that the characterization of covariant positive operator measures on nonunimodular locally compact groups can be obtained by using vector measure theoretic methods, wit…