- #1
Robben
- 166
- 2
Homework Statement
A Steiner Triple System, denoted by ##STS(v),## is a pair ##(S,T)## consisting of a set ##S## with ##v## elements, and a set ##T## consisting of triples of ##S## such that every pair of elements of ##S## appear together in a unique triple of ##T##.
Homework Equations
None
The Attempt at a Solution
My book goes on to say that the number of triples of a ##STS(n)## disjoint from a given triple is ##(n-3)(n-7)/6## but I am not sure how they got that result?
I know that there are ##n(n-1)/6## triples altogether where each point of a triple lies in ##(n-1)/2## triples but I am not sure how they got that ##(n-3)(n-7)/6.##
Last edited: