Can the Pigeonhole Principle Solve This Combinatorics Problem?

  • Thread starter Thread starter LineIntegral
  • Start date Start date
  • Tags Tags
    Combinatorics
Click For Summary
SUMMARY

The discussion centers on applying the Pigeonhole Principle to a combinatorial problem involving a 100x100 matrix where each number from the set {1,2,...,100} appears exactly 100 times. The conclusion reached is that at least one row or column must contain at least 10 different numbers. This is established by assuming the contrary—that every row and column has 9 or fewer distinct numbers—and demonstrating the contradiction that arises from this assumption.

PREREQUISITES
  • Pigeonhole Principle
  • Combinatorial mathematics
  • Matrix theory
  • Basic proof techniques
NEXT STEPS
  • Study the Pigeonhole Principle in-depth
  • Explore combinatorial proofs and their applications
  • Learn about matrix properties and their implications
  • Investigate advanced topics in combinatorial optimization
USEFUL FOR

Students and educators in mathematics, particularly those focusing on combinatorics and proof strategies, as well as anyone interested in the application of the Pigeonhole Principle in problem-solving.

LineIntegral
Messages
9
Reaction score
0

Homework Statement



Let A be a 100x100 matrix such that each number from the set {1,2,...,100} appears exactly 100 times. Prove that there exists a row or column with at least 10 different numbers.

Homework Equations




The Attempt at a Solution



I suspect that I should use the pigeonhole principle, but I can't think of a way to do so.
 
Physics news on Phys.org
so as a start could you look for a contradiction by assuming every row & column can have 9 or less distinct numbers
 
Solved it, thanks :)
 

Similar threads

Replies
2
Views
1K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 1 ·
Replies
1
Views
5K
  • · Replies 1 ·
Replies
1
Views
2K