An antimicrobial agent includes silver-chloro complex salts and chloride, and further oxidizing agents such as sodium hypochlorite or sodium chlorite. The packaging material comprises a base layer of paper or board and polymeric heat-sealable layers on one side of the base layer or, preferably, on both sides thereof. The differencing processing unit performs a difference operation on at least two tree-structured documents, in accordance with difference configuration information regarding the documents. The projected corner canvas which extends into the corner space portion transversely slides to the rear along the winding roller and the front bar of the rectangular canvas while remaining in a spread state, and after that, the projected corner canvas and the rectangular canvas are wound around the winding roller in such a state that the canvases overlap. The first file refers to the base-view stream in monoscopic video playback, and the second file refers to the base-view stream in stereoscopic video playback. The rear-wheel steering angle control device includes a target rear-wheel steering angle calculating device which has a variable coefficient inputting device.