Article
Keywords:
$G$-space; equivariant map; vector; scalar; biscalar
Summary:
In this note, there are determined all biscalars of a system of $s\le n$ linearly independent contravariant vectors in $n$-dimensional pseudo-Euclidean geometry of index one. The problem is resolved by finding a general solution of the functional equation $F(A{\underset{1}{\rightarrow }u},A {\underset{2}{\rightarrow }u},\dots ,A{\underset{s}{\rightarrow }u}) =( \text{sign}( \det A)) F ({\underset{1}{\rightarrow }u},{\underset{2}{\rightarrow }u},\dots ,{\underset{s}{\rightarrow }u}) $ for an arbitrary pseudo-orthogonal matrix $A$ of index one and the given vectors ${\underset{1}{\rightarrow }u}, {\underset{2}{\rightarrow }u},\dots ,{\underset{s}{\rightarrow }u}$.
References:
                        
[1] J. Aczél, S. Gołb: 
Funktionalgleichungen der Theorie der geometrischen Objekte. P.W.N Warszawa, 1960. 
MR 0133763[2] L. Bieszk, E. Stasiak: 
Sur deux formes équivalentes de la notion de $( r,s)$-orientation de la géométrie de Klein. Publ. Math. Debrecen 35 (1988), 43–50. 
MR 0971951[3] J. A. Dieudonné, J. B. Carrell: 
Invariant Theory. Academic Press, New York, 1971. 
MR 0279102[5] E. Stasiak: O pewnym działaniu grupy pseudoortogonalnej o indeksie jeden $O(n,1,R)$ na sferze $S^{n-2}$. Prace Naukowe P. S., 485, Szczecin, 1993.
[6] E. Stasiak: 
Scalar concomitants of a system of vectors in pseudo-Euclidean geometry of index 1. Publ. Math. Debrecen 57 (2000), 55–69. 
MR 1771671 | 
Zbl 0966.53012