fact: Definition BZsum_v2 x y:= let abs_sum := (BZ_val x) +c (BZ_val y) in let abs_diff1 := (BZ_val x) -c (BZ_val y) in let abs_diff2 := (BZ_val y) -c (BZ_val x) in Yo (inc x BZp /\ inc y BZp) (BZ_of_nat abs_sum) (Yo ( ~ inc x BZp /\ ~ inc y BZp) (BZm_of_nat abs_sum) (Yo (inc x BZp /\ ~ inc y BZp) (Yo ( (BZ_val y) <=c (BZ_val x)) (BZ_of_nat abs_diff1) (BZm_of_nat abs_diff2)) (Yo ( (BZ_val x) <=c (BZ_val y)) (BZ_of_nat abs_diff2) (BZm_of_nat abs_diff1)))).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)