Require Export GeoCoq.Tarski_dev.Ch06_out_lines.
Section Sums.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
(** Existence of the sum *)

(* Specifications: *)
Lemma ex_sums : forall A B C D, exists E F, SumS A B C D E F.
(** Commutativity of the sum. *)
Lemma sums_sym : forall A B C D E F, SumS A B C D E F -> SumS C D A B E F.
(** Unicity of the sum. *)
Lemma sums2__cong56 : forall A B C D E F E' F', SumS A B C D E F -> SumS A B C D E' F' ->
Cong E F E' F'.