law of exponentiation

[leesugil]

x^(a + b) = x^a x^b (x^a)^b = x^(a b)

[leesugil]

1. x^(a + b) = x^a * x^b
   • "^" currently has only right-distributivity over { " * ", " / ", NULL }
   • invent something like "left_dist_over_by" with { { " + ", " * ", NULL}, NULL }
2. (x^a)^b = x^(a * b)
   • "^" currently has only right-distributivity over { " * ", " / ", NULL }
   • invent something like "left2right_assoc_by" with { { "^", " * ", NULL}, NULL }

[leesugil]

update included in the upcoming major update for commutativity, associativity and distributive properties