Upper bound on number of productsin AND-OR-XOR expansion of logic functions

The representation of logic functions consisting of an XOR sum of two sum-of-products expressions is considered. The upper bound on the number of products in the representation is shown to be 5·2n-4, which is 37.50% smaller than the upper bound for a sum-of-product expression and 16.67% smaller than the bound for an AND-XOR expression.