(* Basic properties *********************************************************)
-lemma plus_rew: ∀ri1,ri2,rs1,rs2,ti1,ti2,ts1,ts2.
- 〈ri1+ri2, rs1+rs2, ti1+ti2, ts1+ts2〉 =
- plus (〈ri1,rs1,ti1,ts1〉) (〈ri2,rs2,ti2,ts2〉).
-// qed. (**) (* disambiguation of plus fails *)
+(**) (* plus is not disambiguated parentheses *)
+lemma plus_rew: ∀ri1,ri2,rs1,rs2,ti1,ti2,ts1,ts2.
+ 〈ri1+ri2, rs1+rs2, ti1+ti2, ts1+ts2〉 =
+ (〈ri1,rs1,ti1,ts1〉) + (〈ri2,rs2,ti2,ts2〉).
+// qed.
lemma plus_O_dx: ∀c. c = c + 𝟘𝟘.
* #ri #rs #ti #ts <plus_rew //