Library Stdlib.Reals.SplitAbsolu
Require Import Rbasic_fun.
Ltac split_case_Rabs :=
match goal with
| |- context [(Rcase_abs ?X1)] =>
destruct (Rcase_abs X1) as [?Hlt|?Hge]; try split_case_Rabs
end.
Ltac split_Rabs :=
match goal with
| id:context [(Rabs _)] |- _ => generalize id; clear id; try split_Rabs
| |- context [(Rabs ?X1)] =>
unfold Rabs; try split_case_Rabs; intros
end.