**Actually L is the classical Lagrangian of the one-dimensional system considered, πΏ ( π₯ , π₯ Λ ) = π β π = 1 2 π | π₯ Λ | 2 β π ( π₯ ) \displaystyle L(x and the abovementioned "zigzagging" corresponds to the appearance of the terms exp β‘ ( π β π β π = 1 π + 1 πΏ ( π₯ ~ π , π₯ π β π₯ π β 1 π , π ) ) \displaystyle \exp \left(\frac i\hbar \varepsilon \sum _j=1^n+1L\left(\tilde x_j