Hi,(adsbygoogle = window.adsbygoogle || []).push({});

It was a big mistake leaving my assignment till the last minutes. Now i'm stuck on a few questions and got no where to turn to except the net.

Please do give any hints you may have..

Thank You!

1. Let A subset {1,2,3,....,25} where |A| = 9. For any subset B of A let SB denote the sum of the elements in B. Prove that there are distinct subsets C, D of A such that |C|=|D|=5 and SC=SD.

2.Let R subset Z+ X Z+ (Z+ means positive int, and X means cross product) be the relation given by the following recursive definition.

1. (1,1) element of R; and

2. for all (a,b) element of R, the three ordered pairs (a+1,b), (a+1,b+1), and (a+1, b+2) are also in R.

Prove that 2a _> b for all (a,b) element of R.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Pigeonhole problem set

**Physics Forums | Science Articles, Homework Help, Discussion**