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.
(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)))) (Forall (?N) (=> (And (Positive-Integer ?N) (=< ?N (Basis.Dimension ?B))) (Defined (Basis.Vec ?B ?N))))
(Forall (?B ?I) (=> (And (Orthonormal-Basis ?B) (= (Basis.Dimension ?B) (Spatial.Dimension ?V)) (Positive-Integer ?I) (=< ?I (Spatial.Dimension ?V))) (And (Defined (Vector-Component ?V ?I ?B)) (= (Quantity.Dimension (Vector-Component ?V ?I ?B)) (Quantity.Dimension ?V))))) (<=> (Vector-Quantity ?V) (And (Constant-Quantity ?V) (Tensor-Quantity ?V) (= (Tensor-Order ?V) 1) (Forall (?B ?I) (=> (And (Orthonormal-Basis ?B) (= (Basis.Dimension ?B) (Spatial.Dimension ?V)) (Positive-Integer ?I) (=< ?I (Spatial.Dimension ?V))) (And (Defined (Vector-Component ?V ?I ?B)) (= (Quantity.Dimension (Vector-Component ?V ?I ?B)) (Quantity.Dimension ?V))))) (Forall (?U) (=> (And (Unit-Of-Measure ?U) (= (Quantity.Dimension ?U) (Quantity.Dimension ?V))) (Numeric-Tensor (Magnitude ?V ?U)))))) (Forall (?B ?I ?J) (=> (And (Orthonormal-Basis ?B) (= (Basis.Dimension ?B) (Spatial.Dimension ?D)) (Positive-Integer ?I) (=< ?I (Spatial.Dimension ?D)) (Positive-Integer ?J) (=< ?J (Spatial.Dimension ?D))) (And (Defined (Dyad-Component ?D ?I ?J ?B)) (= (Quantity.Dimension (Dyad-Component ?D ?I ?J ?B)) (Quantity.Dimension ?D))))) (<=> (Dyad ?D) (And (Constant-Quantity ?D) (Tensor-Quantity ?D) (= (Tensor-Order ?D) 2) (Forall (?B ?I ?J) (=> (And (Orthonormal-Basis ?B) (= (Basis.Dimension ?B) (Spatial.Dimension ?D)) (Positive-Integer ?I) (=< ?I (Spatial.Dimension ?D)) (Positive-Integer ?J) (=< ?J (Spatial.Dimension ?D))) (And (Defined (Dyad-Component ?D ?I ?J ?B)) (= (Quantity.Dimension (Dyad-Component ?D ?I ?J ?B)) (Quantity.Dimension ?D))))) (Forall (?U) (=> (And (Unit-Of-Measure ?U) (= (Quantity.Dimension ?U) (Quantity.Dimension ?D))) (Numeric-Tensor (Magnitude ?D ?U)))))) (Nth-Domain Basis.Vec 1 Orthonormal-Basis) (=> (Basis.Dimension $X $Y) (Orthonormal-Basis $X)) (Nth-Domain Tensor-To-Matrix 2 Orthonormal-Basis) (=> (= (Tensor-To-Matrix ?T ?Basis) ?M) (Orthonormal-Basis ?Basis)) (Nth-Domain Vector-Component 3 Orthonormal-Basis) (=> (= (Vector-Component ?V ?I ?B) ?S) (Orthonormal-Basis ?B)) (Nth-Domain Dyad-Component 4 Orthonormal-Basis) (=> (= (Dyad-Component ?T ?I ?J ?Basis) ?S) (Orthonormal-Basis ?Basis)) (Nth-Domain The-Vector-Quantity 2 Orthonormal-Basis) (=> (= (The-Vector-Quantity ?M ?B) ?V) (Orthonormal-Basis ?B)) (Nth-Domain The-Dyad 2 Orthonormal-Basis) (=> (= (The-Dyad ?M ?B) ?T) (Orthonormal-Basis ?B)) (=> (And (Dyad ?X) (Dyad ?Y)) (=> (+ ?X ?Y ?Z) (And (Dyad ?Z) (Forall (?B ?I ?J) (=> (And (Orthonormal-Basis ?B) (= (Spatial.Dimension ?X) (Basis.Dimension ?B)) (Positive-Integer ?I) (Positive-Integer ?J) (=< ?I (Spatial.Dimension ?X)) (=< ?J (Spatial.Dimension ?X))) (= (Dyad-Component ?Z ?I ?J ?B) (+ (Dyad-Component ?X ?I ?J ?B) (Dyad-Component ?Y ?I ?J ?B)))))))) (=> (And (Vector-Quantity ?X) (Vector-Quantity ?Y)) (=> (+ ?X ?Y ?Z) (And (Vector-Quantity ?Z) (Forall (?B ?I) (=> (And (Orthonormal-Basis ?B) (= (Spatial.Dimension ?X) (Basis.Dimension ?B)) (Positive-Integer ?I) (=< ?I (Spatial.Dimension ?X))) (= (Vector-Component ?Z ?I ?B) (+ (Vector-Component ?X ?I ?B) (Vector-Component ?Y ?I ?B))))))))