In order to prove identity (
14) we make use of the compatibility condition (
4) as follows
Making use of the commutativity of a superalgebra
and the graded skew-symmetry of bracket we can represent the right-hand sides of the above identities as follows
Summing up the left-hand sides and right-hand sides of the obtained identities, we get identity (
14). The proof of identity (15) is similar to the proof of identity (
14). First we use the compatibility condition (
4) to obtain the following three identities
where
,
,
. Due to the super Jacobi identity the sum of left-hand sides of the above identities is equal to zero. Hence we get
The sum of the first three terms in the above identity is the left-hand side of identity (15). Thus in order to prove identity (15) we need to show that the sum of the last three terms in the above identity is zero. For the first one of them, that is,
(we temporarily omit the coefficient
, which will be taken into account later) we have the super Jacobi identity
Applying to the middle term at the left-hand side of this equality the compatibility condition
and substituting the obtained expression multiplied by
into super Jacobi identity (
21) we get
where
and
. Applying the same calculations to the next two terms in (
20), we get two more identities
Summing up the identities (
22), (23), (24) multiplied by
and
respectively, we obtain
Subtracting the identity (
20) from (
25) we get the identity (15). By virtue of the proven identity (15), the sum of the first three terms in (
20) will be equal to zero. The remaining three terms, after a suitable permutation of the arguments, give the identity (16).
In order to prove the last identity (17) we apply the compatibility condition to the following products
In the first brackets on the right-hand sides of these relations, we rearrange
h and
,
h and
,
h and
. Next we multiply the first relation by
, the second by
and the third by
. Finally we rearrange the brackets at the left-hand side of every relation. We obtain
Summing up the left-hand sides and the right-hand sides of these relations we get the relation, whose left-hand side (multiplied by 1/2) coincides with the left-hand side of the identity (17), but the right-hand side is equal to zero. Indeed the sum of the first terms at the right-hand side of every relation vanishes because of the identity (15). The sum of the second terms vanishes because of the identity (
14). The identity (18) is proved by means of the compatibility condition. In order to prove the identity (19) we take the sum of the three following relations: the compatibility condition for the products
,
and the identity (18) multiplied by 2. This ends the proof of Theorem 2. □