Let X be a compact topological
space, L a non-Archimedean rank 1 valued field and F a uniformly closed
L-algebra of L-valued continuous functions on X. Kaplansky has shown that if F
separates the points of X, then either F consists of all L-valued continuous
functions on X or else all of them which vanish on one point in X. In this paper
analogous results are obtained, in the case that a group of transformations
acts both on X and L, for the invariant L-valued continuous functions on
X.