From: GOTO Kentaro <gotoken@...>
Date: 2007-01-30T02:57:07+09:00
Subject: Re: cartesian product of arrays

On 1/30/07, Trans <transfire@gmail.com> wrote:
>   require 'facets/core/enumerable/op_pow'
>
>   [1,2] ** [3,4,5]
>   => [[1, 3], [1, 4], [1, 5], [2, 3], [2, 4], [2, 5]]

Confusing operand order...

In set theory, e.g., http://mathworld.wolfram.com/Set.html
the notation A^B, where A and B are arbitrary sets, is used to denote the
set of maps from B to A.  Then we get (a**b).size == (a.size)**(b.size)


Gotoken