Allen Herman

Compressions of Totally Positive Matrices

A matrix is called totally positive if all its minors are positive. If a totally positive matrix A is partitioned as

CLASS PRESERVING AUTOMORPHISMS OF BLACKBURN GROUPS

A = (A_{ij})

Using G-algebras for Schur index computation

i,j=1,2,\ldots,k

CLIFFORD CLASSES OF PRIMITIVE CENTRAL SIMPLE G-ALGEBRAS

, in which each block

Equivalence and the Brauer–Clifford Group for G-Algebras over Commutative Rings

A_{ij}

On the Torsion Units of Integral Adjacency Algebras of Finite Association Schemes

is n x n, we show that the k x k compressed matrix given by

Trivial units for group rings over rings of algebraic integers

(\det A_{ij})

UNITARY GROUPS OVER LOCAL RINGS

is also totally positive and that the determinant of the compressed matrix exceeds A when k=2,3. An extension that allows for overlapping blocks is also presented when k=2,3. For

A constructive Brauer-Witt theorem for certain solvable groups

k \geq 4