  In an earlier paper Cooper, Shepard, and Sodano introduced a generalized KdV
equation that can exhibit the kinds of compacton solitary waves that were first
seen in equations studied by Rosenau and Hyman. This paper considers the
PT-symmetric extensions of the equations examined by Cooper, Shepard, and
Sodano. From the scaling properties of the PT-symmetric equations a general
theorem relating the energy, momentum, and velocity of any solitary-wave
solution of the generalized KdV equation is derived, and it is shown that the
velocity of the solitons is determined by their amplitude, width, and momentum.
