semigroup4 http://www.openmath.org/cd/semigroup4.ocd 2006-06-01 2004-06-01 1 1 experimental A CD of functions for morphisms of semigroups. Written by Arjeh M. Cohen 2004-07-07 automorphism_group This is a function with a single argument which must be a semigroup. It refers to the automorphism group of its argument. homomorphism_by_generators This is a function with three arguments the first two of which must be semigroups F and K. The third argument should be a set or a list L of ordered pairs (lists of length 2). Each pair [x,y] from L consists of an element x from F and an element y from K. when applied to F, K, and L, the symbol represents the homomorphism from F to K that maps the first entry x of each pair [x,y] to the second entry y of the same pair.