Zero-dilation Indices of Kms Matrices Hwa-long Gau and Pei

Zero-dilation Index of S_n-matrix and Companion Matrix

Numerical range circumscribed by two polygons

We show that, for any 2n+ 2 distinct points a1, a′ 1, a2, a′ 2, . . . , an+1, a′ n+1 (in this order) on the unit circle, there is an n-by-n matrix A, unique up to unitary equivalence, which has norm one and satisfies the conditions that it has all its eigenvalues in the open unit disc, In − A∗A has rank one and its numerical range is circumscribed by the two (n+ 1)-gons a1a2 · · · an+1 and a′ 1...

Fabrication of Crosslinkable Hollow Fiber Membranes for Pervaporation Dehydration

Integrally-skinned asymmetric Polyetherimide/Poly (vinyl alcohol) (PEI/PVA) hollow fber membranes for pervaporation dehydration were fabricated by non-solvent induced phase inversion. PVA inside the PEI matrix could be crosslinked to provide membrane performance stability during long term operation. The effects of different PEI/PVA blend ratio, external coagulant type and...

Power Indices of Trace Zero Symmetric Boolean Matrices

The power index of a square Boolean matrix A is the least integer d such that A is a linear combination of previous nonnegative powers of A. We determine the maximum power indices for the class of n × n primitive symmetric Boolean matrices of trace zero, the class of n × n irreducible nonprimitive symmetric Boolean matrices, and the class of n×n reducible symmetric Boolean matrices of trace zer...

Upper and lower bounds for numerical radii of block shifts

For an n-by-n complex matrix A in a block form with the (possibly) nonzero blocks only on the diagonal above the main one, we consider two other matrices whose nonzero entries are along the diagonal above the main one and consist of the norms or minimum moduli of the diagonal blocks of A. In this paper, we obtain two inequalities relating the numeical radii of these matrices and also determine ...