A set of n vector-quantities in an n-dimensional vector space which form an ortho-normal basis, the n vector-quantities are linearly independent and the scalar product of any two is the identity-scalar.
(=> (Orthonormal-Basis ?B) (And (Forall (?N) (=> (And (Positive-Integer ?N) (=< ?N (Basis.Dimension ?B))) (Defined (Basis.Vec ?B ?N)))) (Forall (?N1 ?N2) (=> (And (Positive-Integer ?N1) (Positive-Integer ?N2) (=< ?N1 (Basis.Dimension ?B)) (=< ?N2 (Basis.Dimension ?B))) (=> (= ?N1 ?N2) (= (Dot (Basis.Vec ?B ?N1) (Basis.Vec ?B ?N2)) 1)) (=> (/= ?N1 ?N2) (= (Dot (Basis.Vec ?B ?N1) (Basis.Vec ?B ?N2)) 0))))))