us assume the power law small- x asymptotic behavior for the electric and magnetic gluon densities For the forward like functions G ( E,M ) 0 ( x ) the power law behavior (62) results in The contributions of the forward like functions G ( E,M ) 0 ( x ) into Im A g ( E,M ) have the following asymptotic behavior for ξ ∼ 0: In this section we discuss some aspects of GPD modelling in the framework of the dual parametrization. The important characteristics of the particular GPD model is the so-called skewness effect (also known as the skewness ratio). In [13, 14] it was suggested to define the characteristics of the skewness effect for quark and gluon GPDs H q, g for t = 0 as ratios of the GPDs on the cross-over line x = ξ to the appropriate parton distribution functions, to which GPDs are reduced in the forward limit. Thus, for quark GPD H q the skewness ratio is defined according to VI. SKEWNESS EFFECT FOR SMALL ξ IN THE DUAL PARAMETRIZATION g ( E, M $^{)}$( x ) ∼ 1 x α . (62) G ( E ) 0 ( x ) ∼ 3(1 + 2 α ) ( α + 1)( α + 2) 1 x α ; G ( M ) 0 ( x ) ∼ 3(1 + 2 α ) α ( α + 1)( α + 2) 1 x α . (63) Im A g ( E,M ) G$_{0}$ ( ξ ) ∼ 2 α $^{+2}$Γ( 1 $_{2}$)Γ( 3 2 + α ) Γ(3 + α ) 1 ξ α . (64) r q = H $^{q}$( x = ξ, ξ, t = 0) H $^{q}$( ξ, 0 , t = 0) = H $^{q}$( ξ, ξ, 0) q ( ξ ) , (65) r g = H $^{g}$( x = ξ, ξ, t = 0) H $^{g}$( ξ, 0 , t = 0) = H $^{g}$( ξ, ξ, 0) ξg ( ξ ) . (66) while for gluon GPD H g it reads It is usually assumed that the small- ξ the asymptotic behavior of quark GPD on the cross over trajectory and the corresponding PDF is governed by the same leading Regge 20