On the Clebsch-Gordan Problem in Prime Characteristic

We study the tensor product of an induced module and Weyl module, for the special linear group of order two over an algebraically closed field of positive characteristic. We are primarily concerned with the decomposition of such modules into indecomposable summands, and construct a method which allows one to give the decomposition for any such module in any characteristic. We also develop a variety of other techniques to give the decomposition in particular cases. Furthermore, we give a complete account of exactly when such a module is a tilting module for all primes, and give a number of results in a more general setting.