the imaginary part of the action. One can notice that taking reversed Hermicity (anti-Hermitian) electromagnetic potential $A_{\mu}$ in (, ) the imaginary terms are moved to the real part. With this trick and the $\Lambda^2\to\infty$ limit we can calculate all form factors from () within our scheme and not referring to the nonregularized action ().

Now, taking into account (), () and (-) we can write down the operator exponent contributing to the electromagnetic current as:

$$\openup 3\jot   \eqalign{
&\int^{+\infty}_{-\infty} {d\omega\over 2\pi} \ \exp [-\tau W]
\ \simeq \
- \tau \int_{-\infty}^{+\infty} {d\omega\over 2\pi} \sum_n
e^{-\tau \omega^2} \langle n \vert V \vert n \rangle \, + \cr
&+ \tau^2 \int_{-\infty}^{+\infty} {d\omega\over 2\pi}
\sum_{m,n} e^{-\tau \omega^2} \
\vert \langle n\vert V \vert m \rangle \vert^2
\int^1_0 d\beta \int^{1-\beta}_0 d\alpha \
e^{-\tau(1-\beta)\epsilon^2_n} \
e^{-\tau \beta \epsilon^2_m} \ , \cr  }
 \eqno(\EXPANSp)$$

where the terms quadratic and higher in $\Omega$ are neglected and because of the derivative in () only the terms linear in potentials are present. To compute the functional (space-time) trace we use the Hamiltonian (), like for the action (). Here, the vectors $\vert n \rangle$ denotes the eigenfunctions $\psi_n(x)$ corresponding to the eigenvalues $\epsilon_n$.

We cannot perform the $\omega$-integrals 