MathDB
n set with 4 elements

Source: 0

April 28, 2009
algorithmabstract algebragroup theory

Problem Statement

There are n n sets having 4 4 elements each. The difference set of any two of the sets is equal to one of the n n sets. n n can be at most ? (A difference set of AA and BB is (AB)(BA) (A\setminus B)\cup(B\setminus A) )
<spanclass=latexbold>(A)</span> 3<spanclass=latexbold>(B)</span> 5<spanclass=latexbold>(C)</span> 7<spanclass=latexbold>(D)</span> 15<spanclass=latexbold>(E)</span> None<span class='latex-bold'>(A)</span>\ 3 \qquad<span class='latex-bold'>(B)</span>\ 5 \qquad<span class='latex-bold'>(C)</span>\ 7 \qquad<span class='latex-bold'>(D)</span>\ 15 \qquad<span class='latex-bold'>(E)</span>\ \text{None}