[1XC A graphical interface[0X Here we describe a Tcl/Tk interface to specify numerical semigroups. [1XC.1 Graphical interface[0X [1XC.1-1 XNumericalSemigroup[0m [2X> XNumericalSemigroup( [0X[3X[s][0X[2X ) _______________________________________[0Xfunction This function pops up a Tcl/Tk window which allows the specification of numerical semigroups. The optional argument [3Xs[0m is a numerical semigroup whose definition becomes displayed in the graphical interface. The interface is very simple, it allows to specify a numerical semigroup by its generators or a (proportionally) modular numerical semigroup by its (proportionally) modular condition. The [5XGAP[0m variable by which the semigroup will be known must also be specified. The interface also allows to apply some functions to the semigroup, namely [2XAperyListOfNumericalSemigroupWRTElement[0m ([14X3.1-5[0m), [2XDrawAperyListOfNumericalSemigroup[0m ([14X3.1-6[0m), [2XSmallElementsOfNumericalSemigroup[0m ([14X3.1-3[0m), [2XGapsOfNumericalSemigroup[0m ([14X3.3-1[0m), [2XFrobeniusNumberOfNumericalSemigroup[0m ([14X3.2-1[0m) and [2XMinimalPresentationOfNumericalSemigroup[0m ([14X4.1-2[0m). Finally, it is also possible to add functions to this list and remove them. [4X--------------------------- Example ----------------------------[0X [4Xgap> s:=RandomNumericalSemigroup(3,9);[0X [4X<Numerical semigroup with 3 generators>[0X [4Xgap> XNumericalSemigroup(s);[0X [4X------------------------------------------------------------------[0X This would pop up the following window: