+Each space involves zero or more parameters and zero, one or two
+tuples of set or input/output dimensions. The parameters and dimensions
+are identified by an C<isl_dim_type> and a position.
+The type C<isl_dim_param> refers to parameters,
+the type C<isl_dim_set> refers to set dimensions (for spaces
+with a single tuple of dimensions) and the types C<isl_dim_in>
+and C<isl_dim_out> refer to input and output dimensions
+(for spaces with two tuples of dimensions).
+Local spaces (see L</"Local Spaces">) also contain dimensions
+of type C<isl_dim_div>.
+Note that parameters are only identified by their position within
+a given object. Across different objects, parameters are (usually)
+identified by their names or identifiers. Only unnamed parameters
+are identified by their positions across objects. The use of unnamed
+parameters is discouraged.