MATHEMATICS
Canonical system of basic invariants for unitary group $W(K_5)$
O. I. Rudnitskii Vernadsky Crimean
Federal University, Simferopol, Russian Federation
Abstract:
For a finite group
$G$ generated by reflections in the
$n$-dimensional unitary space
$U^n$, the algebra
$I^G$ of all
$G$-invariant polynomials
$f(x_1,\dots,x_n)$ is generated by
$n$ algebraically independent
homogeneous polynomials
$f_i\in I^G$ with
$\mathrm{deg}\,f_i=m_i$ (
$i=\overline{1,n}$);
$m_1\leqslant m_2\leqslant\dots\leqslant m_n$ (Shephard G. C., Todd J. A.).
According to Nakashima N., Terao H., and Tsujie S., system
$\{f_1,\dots, f_n\}$ of basic invariants of
the group
$G$ is said to be canonical if it satisfies the following system of partial differential equations:
$$
\overline{f}_i(\partial) f_j=0,\quad i,j=\overline{1,n}\ (i<j),
$$
where the differential operator
$\overline{f}_i(\partial)$ is obtained from polynomial
$f_i$ if each its coefficient is replaced by the complex conjugate and each variable
$x_k$ is replaced by
$\frac\partial{\partial x_k}$.
In the previous works, the author obtained in an explicit form canonical systems of basic invariants for all finite primitive unitary groups
$G$ generated by reflections in unitary spaces of dimensional
$2$,
$3$, and
$4$.
In this paper, canonical systems of basic invariants were constructed in an explicit form for
unitary groups
$W(K_5)$ generated by reflections in space
$U^5$.
Keywords:
Unitary space, reflection, reflection groups, algebra of invariants, basic invariant, canonical system of basic invariants.
UDC:
514.7
MSC: 51F15;
14L24 Received: 04.12.2018
DOI:
10.17223/19988621/58/3