MathDB
Arrangement of an n x n table with entries in {0, 1}.

Source: Tuymaada 2004, day 2, problem 3. - Author : O. Vanyushina.

May 25, 2007
vectorfunctioninductioncombinatorics proposedcombinatorics

Problem Statement

Zeroes and ones are arranged in all the squares of n×nn\times n table. All the squares of the left column are filled by ones, and the sum of numbers in every figure of the form [asy]size(50); draw((2,1)--(0,1)--(0,2)--(2,2)--(2,0)--(1,0)--(1,2));[/asy] (consisting of a square and its neighbours from left and from below) is even. Prove that no two rows of the table are identical.
Proposed by O. Vanyushina