On symmetric semialgebraic sets and orbit spaces
Volume 44 / 1998
Banach Center Publications 44 (1998), 37-50 DOI: 10.4064/-44-1-37-50
For a symmetric (= invariant under the action of a compact Lie group G) semialgebraic basic set C, described by s polynomial inequalities, we show, that C can also be written by s + 1 G-invariant polynomials. We also describe orbit spaces for the action of G by a number of inequalities only depending on the structure of G.