${\Psi }^{\left(\mathrm{mathrm}U\right)}\left(\mathrm{mathbf}x\right)={\int }_{-\infty }^{\infty }{\int }_{-\infty }^{\infty }\exp \left(i{\Phi }^{\left(\mathrm{mathrm}U\right)}\right(s,t;\mathrm{mathbf}x\left)\right)\mathrm{mathrm}ds\mathrm{mathrm}dt$