I would like to propose that the + operator be a synonym for | (union) on sets. IMHO, the succinct power of being able to say sum(list_of_sets, set()) as opposed to import operator reduce(operator.and_, list_of_sets, set()) far outweighs any problems with having two operators for union. The sum paradigm is certainly more readable as well. I realize that a function named "unionall" could be defined trivially, but with a built-in already serving the purpose in a readable and reasonable way, it seems silly to not use it. I anticipate that someone will ask why such a paradigm should be available for union as opposed to the other set operations. My answer is that several standard algorithms rely on a union over a sequence of sets; one example is the construction of the "follow" set in constructing an LL or SLR parser, and I know I've seen others that I cannot remember off the top of my head. There is even a mathematical symbol (big-U) for it akin to the summation sign (uppercase sigma). Any feedback? Brandon