Konieczny: add example to doc

Author: MT-resource-bot

include/libsemigroups/konieczny.hpp

@@ -61,6 +61,18 @@ namespace libsemigroups {
   //! from a finite over-monoid which acts on sets on the left and on the right
   //! in an appropriate way. The prototypical example, as described by
   //! %Konieczny, is the monoid of boolean matrices.
+  //!
+  //! \code
+  //!  using namespace libsemigroups;
+  //!  const std::vector<BMat8> reg_bmat4_gens
+  //!      = {BMat8({{0, 1, 0, 0}, {1, 0, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}}),
+  //!         BMat8({{0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {1, 0, 0, 0}}),
+  //!         BMat8({{1, 0, 0, 0}, {1, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}}),
+  //!         BMat8({{0, 0, 0, 0}, {0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}})};
+  //!  Konieczny<BMat8> S(reg_bmat4_gens);
+  //!  S.size();   // returns 63904
+  //!  S.number_of_idempotents();   //returns 2360
+  //! \endcode
 
   //! \ingroup konieczny_group
   //!