Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: State space formulas for a suboptimal rational Leech problem II:
  Parametrization of all solutions   For the strictly positive case (the suboptimal case), given stable rational
matrix functions $G$ and $K$, the set of all $H^\infty$ solutions $X$ to the
Leech problem associated with $G$ and $K$, that is, $G(z)X(z)=K(z)$ and
$\sup_{|z|\leq 1}\|X(z)\|\leq 1$, is presented as the range of a linear
fractional representation of which the coefficients are presented in state
space form. The matrices involved in the realizations are computed from state
space realizations of the data functions $G$ and $K$. On the one hand the
results are based on the commutant lifting theorem and on the other hand on
stabilizing solutions of algebraic Riccati equations related to spectral
factorizations.

18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat