fact: Definition w : rat := a'0_ub * a'1_ub * a'2_ub * a'3_ub * a'4_ub ^ 2.
imports: ZArith mathcomp(all_ssreflect all_algebra all_field) extra_mathcomp tactics binomialz floor arithmetics posnum rat_of_Z hanson_elem_arith hanson_elem_analysis