Alperin's weight conjecture (1987) is a central open problem in the modular representation theory of nite groups, predicting that the number of simple modules of a block is equal to the number of its weights. Over the past decades, many di erent approaches
to this conjecture have been developed, and it has been a driving force in the development of block theory and local-global methods in representation theory. In this talk, we will present an equivalent reformulation of Alperin's conjecture in terms of diagonal p-permutation functors. This is joint work with Robert Boltje and Serge Bouc.