Counting with groups and rings.
Covariance Structure of Principal Components for Three-Part Compositional Data
Statistical analysis of compositional data, multivariate observations carrying only relative information (proportions, percentages), should be performed only in orthonormal coordinates with respect to the Aitchison geometry on the simplex. In case of three-part compositions it is possible to decompose the covariance structure of the well-known principal components using variances of log-ratios of the original parts. They seem to be helpful for the interpretation of these special orthonormal coordinates....
Covering in the set of principal ideals in the semigroup of binary relations.
CR singular immersions of complex projective spaces.
Criteria for Positive Definiteness of Some Band Matrices.
Criteria of unitary equivalence of Hermitian operators with a degenerate spectrum.
Cyclic products and an inequality for determinants
Cylinder matrices