mathlib

56f6c8e8 - chore(algebra/big_operators/intervals): Move and golf sum_range_sub_sum_range (#13359)

chore(algebra/big_operators/intervals): Move and golf sum_range_sub_sum_range (#13359) Move sum_range_sub_sum_range to a better file. Also implemented the golf demonstrated in this paper https://arxiv.org/pdf/2202.01344.pdf from @spolu.