Definition row2 {R : ringType} (a b : R) : 'rV[R]_2 :=
\row_p [eta \0 with 0 |-> a, 1 |-> b] p.
Definition a : (@Vector R 1) := row2 0 0.
Definition b : (@Vector R 1) := row2 0 1.
Definition c : (@Vector R 1) := row2 1 0.

(* Specifications: *)
Lemma row2_eq (a b c d : R) : row2 a b == row2 c d = ((a == c) && (b == d)).
Lemma row2_eq0 (a b : R) : row2 a b == 0 = ((a == 0) && (b == 0)).
Lemma a_eq0 : a = 0.
Lemma betR_bca : betR b c a = 1.
Lemma betR_cab : betR c a b = 0 \/ betR c a b = 1.
Lemma lower_dim : ~ (bet a b c \/ bet b c a \/ bet c a b).
End Tarski2D.