where B and F are a (n - 2)-form and a

2-form respectively on M and which takes values in the Lie algebra g of G.

[OMEGA] = ([[OMEGA].sup.i.sub.j]) is called curvature

2-form or the Riemannian curvature tensor associated with the connection [theta] and it is written as

For example, with two 1-forms e and h in 3-D space, their wedge product e [conjunction] h is a

2-form. And this corresponds to the fact that the cross product of two vector fields E(r) and H(r) gives rise to a new vector field S(r) = E x H.

G is also equivalent to a pair ([gamma], [psi]) where [gamma] is a Riemannian metric and [psi] is a

2-form on M.

The fundamental

2-form [PHI] on an almost contact metric manifold [M.sup.2n+1] is defined by [PHI](X, Y) = g(X, [phi]Y) for any vector fields X and Y on [M.sup.2n+1].

We recall that multiplicative of a

2-form w is defined by

The samples show typical diffraction peak of monoclinic

2-form crystals, indicating that during cold-temperature stretching no crystal transformation occurrence.

For instance, if [[A.sub.12]d[x.sub.1] [and] d[x.sub.2]] = {[A.sub.12]d[x.sub.1] [and] d[x.sub.2], -[A.sub.12]d[x.sub.2] [and] d[x.sub.1]} [member of] [E.sup.2], then [A.sub.12]d[x.sub.1] [and] d[x.sub.2] is chosen as a representative of the considered

2-form. By the constructions described above we obtain a sequence of vector spaces [E.sup.0] : = [K.sup.*], [E.sup.1] := E, [E.sup.2], [E.sup.3], [E.sup.p], ...

So, we define the electromagnetic strength F

2-form as:

The

2-form [PHI] on [M.sup.2n+1] defined by [PHI] (X, Y) = g (X,(Y) is called the fundamental

2-form of the almost contact metric manifold [M.sup.2n+1].