Thread: Help!!c problem in math

  1. #1
    Registered User
    Join Date
    Oct 2007
    Posts
    1

    Question Help!!c problem in math

    Code:
    we call s is a topology of a set S,if s is a set of several subsets of S which satisfied: 
    1.s contains  empty set and S; 
    2.if a and b belong to s ,then the intersection of a and b also belongs to s;
    3.the unity of several sets which belong to s is also belongs to s.
    
    assume a set S = {1,2,...,n} . How many topologies of S do we have?

  2. #2
    Woof, woof! zacs7's Avatar
    Join Date
    Mar 2007
    Location
    Australia
    Posts
    3,459
    Last edited by zacs7; 10-06-2007 at 03:07 AM. Reason: Spelt it's wrong... lol

  3. #3
    and the hat of int overfl Salem's Avatar
    Join Date
    Aug 2001
    Location
    The edge of the known universe
    Posts
    39,656
    Nothing to do with C, just a simple visit to mathworld should suffice.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

Popular pages Recent additions subscribe to a feed

Similar Threads

  1. Memory problem with Borland C 3.1
    By AZ1699 in forum C Programming
    Replies: 16
    Last Post: 11-16-2007, 11:22 AM
  2. math problem
    By Chaplin27 in forum A Brief History of Cprogramming.com
    Replies: 2
    Last Post: 06-09-2005, 02:37 PM
  3. Math Problem....
    By NANO in forum A Brief History of Cprogramming.com
    Replies: 18
    Last Post: 11-11-2002, 04:37 AM
  4. math problem
    By unixOZ in forum Linux Programming
    Replies: 4
    Last Post: 10-19-2002, 12:17 AM
  5. Little math problem
    By Thantos in forum A Brief History of Cprogramming.com
    Replies: 2
    Last Post: 10-27-2001, 07:44 PM