MathDB
Binary prism

Source: Romanian District Olympiad 2006, Grade 10, Problem 3

March 11, 2006
geometry3D geometryprismcombinatorics proposedcombinatorics

Problem Statement

We say that a prism is binary if there exists a labelling of the vertices of the prism with integers from the set {1,1}\{-1,1\} such that the product of the numbers assigned to the vertices of each face (base or lateral face) is equal to 1-1. a) Prove that any binary prism has the number of total vertices divisible by 8; b) Prove that any prism with 2000 vertices is binary.