Hint Resolve equilateral_strict_neq : equilateral.

(* Specifications: *)
Lemma equilateral_strict_swap_1 :
equilateral_strict A B C ->
equilateral_strict A C B.
Lemma equilateral_strict_swap_2 :
equilateral_strict A B C ->
equilateral_strict B A C.
Lemma equilateral_strict_swap_3 :
equilateral_strict A B C ->
equilateral_strict B C A.
Lemma equilateral_strict_swap_4 :
equilateral_strict A B C ->
equilateral_strict C A B.
Lemma equilateral_strict_swap_5 :
equilateral_strict A B C ->
equilateral_strict C B A.