zero pencil
[Z, U] = zeropen(Sl)
a linear system (syslin list in state-space form [A,B,C,D])
matrix pencil Z=s*E-A
square orthogonal matrix
Z= sE - F is the zero pencil of the linear system Sl with
matrices [A,B,C,D]. Utility function.
With U row compression of [B;D] i.e, U*[B;D]=[0;*]; one has:
The zeros of Z are the zeros of Sl.