The SmallBasis Operation

One natural operation is called SmallBasis. We begin by describing an idealized version of it. SmallBasis associates to a finite sequence , a subset Y of X such that if and only if . for each .

Note that SmallBasis(X) depends on the order of the 's in the sequence X.

The reason that SmallBasis cannot be fully implemented on a computer is that one cannot in general decide whether or not .

• Approximation of the SmallBasis operation