(* Authors: Albert Qiaochu Jiang *) theory mathd_numbertheory_412 imports Complex_Main begin theorem mathd_numbertheory_412: fixes x y :: nat assumes h0 : "x mod 19 = (4:: nat)" and h1 : "y mod 19 = (7:: nat)" shows "(x+1)^2 * (y+5)^3 mod 19 = (13:: nat)" sorry end