where do I find the definition of class objects in spatstat

Question

I would like to know what kind of information does an object of class Spatialpolygons has versus an object of class Polygons.

Answer 1

If you open help pages for Polygon or SpatialPolygons (doesn't really matter, it will lead you to the same page), you can click on SpatialPolygons-class and Polygons-class links. There, you can see which slots each class contains.

Polygon-class as an example:

Slots

ringDir:
    Object of class "integer"; the ring direction of the ring (polygon) coordinates, holes are expected to be anti-clockwise 
labpt:
    Object of class "numeric"; an x, y coordinate pair forming the label point of the polygon 
area:
    Object of class "numeric"; the area of the polygon 
hole:
    Object of class "logical"; does the polygon seem to be a hole 
coords:
    Object of class "matrix"; coordinates of the polygon; first point should equal the last point