“…In the present paper, we analyze the Sommerfeld solution to the stationary diffraction by a half-plane, which corresponds to the case = 0, 21 (see also Sommerfeld 22,23 ). In this case, our results [15][16][17][18][19][20] are not applicable directly. Nevertheless, we prove for the first time that even in this case, the LAP holds, ie,…”