Second, the ''difference map'' (or the ''chordal transformation'') <math>\operatorname{D}G = (\operatorname{D}G_1, \operatorname{D}G_2) : \operatorname{E}U^\circ \to \operatorname{E}X^\circ</math> is defined in a component-wise fashion as the boolean sum of the initial proposition <math>G_j\!</math> and the ''enlarged'' or ''shifted'' proposition <math>\operatorname{E}G_j,</math> for <math>j = 1, 2,\!</math> in accord with following pair of equations: | Second, the ''difference map'' (or the ''chordal transformation'') <math>\operatorname{D}G = (\operatorname{D}G_1, \operatorname{D}G_2) : \operatorname{E}U^\circ \to \operatorname{E}X^\circ</math> is defined in a component-wise fashion as the boolean sum of the initial proposition <math>G_j\!</math> and the ''enlarged'' or ''shifted'' proposition <math>\operatorname{E}G_j,</math> for <math>j = 1, 2,\!</math> in accord with following pair of equations: |