MathDB
IMC 2006, problem 3, day 1

Source:

July 22, 2006
linear algebramatrixRing TheoryIMCcollege contests

Problem Statement

Let AA be an nnxnn matrix with integer entries and b1,b2,...,bkb_{1},b_{2},...,b_{k} be integers satisfying detA=b1b2...bkdetA=b_{1}\cdot b_{2}\cdot ...\cdot b_{k}. Prove that there exist nnxnn-matrices B1,B2,...,BkB_{1},B_{2},...,B_{k} with integers entries such that A=B1B2...BkA=B_{1}\cdot B_{2}\cdot ...\cdot B_{k} and detBi=bidetB_{i}=b_{i} for all i=1,...,ki=1,...,k.