valid(object, ...)NA.valid is generic,
with methods for the classes "ppm" and "dppmodel". An object representing a point process is called valid if
all its parameter values are known (for example, no parameter
takes the value NA or NaN) and the parameter values
correspond to a well-defined point process (for example, the
parameter values satisfy all the constraints that are imposed by
mathematical theory.)
See the methods for further details.
valid.ppm,
valid.detpointprocfamily