do not use abbreviation

Boolean_set_operations_2/doc/Boolean_set_operations_2/Boolean_set_operations_2.txt

@@ -407,7 +407,7 @@ aforementioned free functions is actually realized by a set overriding
 member function.
 
 member functions of the `Polygon_set_2`
-(resp. `General_polygon_set_2`) that perform Boolean set-operations
+(respectively `General_polygon_set_2`) that perform Boolean set-operations
 come in two flavors: for example, `S.join(P, Q)` computes the union of
 \f$ P\f$ and \f$ Q\f$ and assigned the result to \f$ S\f$, while
 `S.join(P)` performs the operation \f$ S \longleftarrow S \cup P\f$.
@@ -579,8 +579,8 @@ template, as described above, an instance of the
 `Arr_polyline_traits_2` class template; see Section \ref
 arr_ssectr_polylines in the 2D Arrangements package.
 
-<li>Each input linear polygon (resp. linear polygon with holes) is
-converted into a general polygon (resp. general polygon with holes)
+<li>Each input linear polygon (respectively linear polygon with holes) is
+converted into a general polygon (respectively general polygon with holes)
 bounded by \f$x\f$-monotone polylines. Then, the resulting generl
 polygons, which are also bounded by \f$x\f$-monotone polylines, are
 converted back to standard polygons.