The Friendship Theorem and Minimax Theorems
  We propose a generalization of Halls marriage theorem. The generalization given here provides a necessary sufficient condition for arranging a successful friendship among n number of k sets. We define multimatrix, multideterminant, multideterminantal monomials, and show that the existence of a nonzero multideterminantal monomial implies the desired existence of a successful friendship. Every nonzero multideterminantal monomial represents a possible way to achieve a successful friendship. A generalization of Mengers theorem and that of some minimax theorems is stated. 
Dhananjay P. Mehendale