group theory

[tepid gale]

Two sets containing 2 and 4 elements then nunber of subsets will be 2^8...but how to find number of subsets which contains 3 and more elements?

[lament root]

1. Wait patiently for a helper to come along.
2. Once someone helps you, say thank you and close the thread with:

+close

3. Feel free to nominate the person for helper of the week in #helper-nominations
4. Do not ping the mods, unless someone is breaking the rules.
5. If you're happy with the help you got here, and the server overall, you can contribute financially as well:

[tepid gale]

@lusty onyx

[lusty onyx]

count how many subsets there are that contain at most 2 elements

for example if there are n elements then you have the empty set, all singleton subsets and n choose 2 subsets with two elements

so the number you want is

$$ 2^n - \left(1+n+\binom{n}{2}\right) $$

[wary otter]

aL

[tepid gale]

Ohh got it

256-1-8-28

+close