isabelle/valid/mathd_numbertheory_466.thy (11 lines of code) (raw):
(*
Authors: Wenda Li
*)
theory mathd_numbertheory_466
imports Complex_Main "HOL-Computational_Algebra.Computational_Algebra"
"HOL-Number_Theory.Number_Theory"
begin
theorem mathd_numbertheory_466:
"(\<Sum> k< 11. k) mod 9 = (1::nat)"
by eval
end