Pott has shown that the product of two semiregular relative difference sets in commuting groups El and E2 relative to their intersection subgroup C is itself a semiregular relative difference set in their amalgamated direct product. We generalise this result in the case that C is central in El and in E2 by using an equivalence with corresponding co cycles 7./Jl and 'l/J2' We prove that in the c...

Lack of understanding of the extension, education, and development practitioners’ role and their contribution to sustainable agriculture is the main challenge of sustainability projects in Iran. Accordingly, the aim of this study was toidentify the extension system that has been more successful in sustainable horticulture. The population consisted of 22 pioneer farmers that had used or are usin...

‎‎we exhibit an explicit construction for the second cohomology group‎ ‎$h^2(l‎, ‎a)$ for a lie ring $l$ and a trivial $l$-module $a$‎. ‎we show how the elements of $h^2(l‎, ‎a)$ correspond one-to-one to the‎ ‎equivalence classes of central extensions of $l$ by $a$‎, ‎where $a$‎ ‎now is considered as an abelian lie ring‎. ‎for a finite lie‎ ‎ring $l$ we also show that $h^2(l‎, ‎c^*) cong m(l)$‎...

Knee extension is always performed with coordinated contractions of multiple quadriceps muscle components; however, how the load is shared among them under normal and pathological conditions is unclear. We hypothesized that: the absolute moment generated by each quadriceps component increases with the total knee extension moment; the relative contribution and its dependence on the total knee ex...

extended distribution of digicash has commercial, socio-economic as well as political effects. from the economic viewpoint, the most crucial effect of digicash use extension takes place on money supply, monetary policies and central bank. because digicash is capable of being replaced by bank notes and the coins, it is possible that digicash gradually takes the place of the central bank money an...

We study the universal enveloping associative conformal algebra for central extension of a current Lie at locality level N = 3. A standard basis defining relations this is explicitly calculated. As corollary, we find linear free commutative relative to 3 on generators.