e.g. Could a minimum width of 50 cm and a maximum width of 200 cm be assumed, with a tendency toward the narrow end, meaning that in the absence of any width tag, a path could be rendered as 1.5 m wide, which physically allows foot, bicycle, and horse access.
there is no minimum width, but width for unpaved ways is generally more difficult to estimate. For a path on bare ground, being just 20-30 cm wide on the ground is no problem if there is space above for the body