When is a Kirillov orbit a linear variety?

When Is a Schubert Variety Gorenstein ?

When Is a Group Action Determined by It’s Orbit Structure?

We present a simple approach to questions of topological orbit equivalence for actions of countable groups on topological and smooth manifolds. For example, for any action of a countable group Γ on a topological manifold where the fixed sets for any element are contained in codimension two submanifolds, every orbit equivalence is equivariant. Even in the presence of larger fixed sets, for actio...

When Is a Linear System Conservative ?

We consider infinite-dimensional linear systems without a-priori wellposedness assumptions, in a framework based on the works of M. Livšic, M. S. Brodskĭı, Y. L. Smuljan, and others. We define the energy in the system as the norm of the state squared (other, possibly indefinite quadratic forms will also be considered). We derive a number of equivalent conditions for a linear system to be energy...

SOLVING FUZZY LINEAR SYSTEMS BY USING THE SCHUR COMPLEMENT WHEN COEFFICIENT MATRIX IS AN M-MATRIX

This paper analyzes a linear system of equations when the righthandside is a fuzzy vector and the coefficient matrix is a crisp M-matrix. Thefuzzy linear system (FLS) is converted to the equivalent crisp system withcoefficient matrix of dimension 2n × 2n. However, solving this crisp system isdifficult for large n because of dimensionality problems . It is shown that thisdifficulty may be avoide...

Linear Pentapods with a Simple Singularity Variety

There exists a bijection between the configuration space of a linear pentapod and all points (u,v,w, px, py, pz)∈R located on the singular quadric Γ : u2+v2+w2 = 1, where (u,v,w) determines the orientation of the linear platform and (px, py, pz) its position. Then the set of all singular robot configurations is obtained by intersecting Γ with a cubic hypersurface Σ in R6, which is only quadrati...