[postgis-devel] [PostGIS] #671: ST_isempty( GEOMETRYCOLLECTION(GEOMETRYCOLLECTION(EMPTY)) ) returns false

[Fabian Riethmayer]

I think this is the correct behaviour. 

For me GEOMETRYCOLLECTION(GEOMETRYCOLLECTION(EMPTY)) is the (power) set of the 
empty set. 

-  P(∅) = {∅}
-  |{∅}| = 1 
  => not empty

and  ST_isempty( GEOMETRYCOLLECTION(GEOMETRYCOLLECTION(EMPTY)) ) should return 
false.