integer xy-net
Source: Romanian TST 1978, Day 2, P1
September 29, 2018
analytic geometrynumber theorycartesian plane
Problem Statement
Associate to any point in the integer net of the cartesian plane a real number so that
a_{h,k}=\frac{1}{4}\left( a_{h-1,k} +a_{h+1,k}+a_{h,k-1}+a_{h,k+1}\right) , \forall h,k\in\mathbb{Z} . a) Prove that it´s possible that all the elements of the set are different.
b) If so, show that the set hasn´t any kind of boundary.