Thanks for the pages. I always have trouble with these. Looks good to me but better get some other opinions too.
In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.
Those pages are excellent; you have made it crystal clear. If only I'd had that clarity 46 years ago ...
You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei