Hi. I am doing some work in natural language processing and am trying to work out a combinatory formula. I want to determine a general formula for:
How many combinations of subgroups size k are there for a group of size n that preserve the order in n?
E.g. How many groups of 5 numbers are there between 1 and 100 that are in ascending order?
I know for many this will be basic but my combinatorics is really rusty. Any advice much appreciated. C.