On Oct 12, 2013, at 6:47 PM, Steven D'Aprano <steve@pearwood.info> wrote:

the proposal is not to eliminate duplicates from 
the population, but from the permutations themselves.

I'm curious about the use cases for this.
Other than red/blue marble examples and some puzzle problems,
does this come-up in any real problems?  Do we actually need this?


Raymond