p,l,u,s,pl,pu,ps,lu,ls,us,plu,pls,pus,lus
check those and count them.
Let C = {p, l, u, s}. How many proper subsets does C have?
2 answers
Most texts include the null set, or{}, as a subset of every set.
So for n elements in any set there would be 2^n - 1 proper subsets.
In your case there would be 15.
Notice we excluded the set itself, or {p,l,u,s}, from the list of 'proper' subsets
So for n elements in any set there would be 2^n - 1 proper subsets.
In your case there would be 15.
Notice we excluded the set itself, or {p,l,u,s}, from the list of 'proper' subsets