<Appendix><Heading>A graphical interface</Heading>

	Here we describe a Tcl/Tk interface to specify numerical semigroups.

<Section><Heading>Graphical interface</Heading>

<ManSection>
	<Func Name="XNumericalSemigroup" Arg="[s]"></Func>
            <Description>
				This function pops up a Tcl/Tk window which allows the specification
				of numerical semigroups.
				The optional argument <A>s</A> is a numerical semigroup
				whose definition becomes displayed in the graphical interface.
				<P/>
				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 &GAP; variable by which the semigroup will be known must also
				be specified.
				<P/>
				The interface also allows to apply some functions to the semigroup,
				namely <Ref Func="AperyListOfNumericalSemigroupWRTElement" />,
				<Ref Func="DrawAperyListOfNumericalSemigroup" />,
				<Ref Func="SmallElementsOfNumericalSemigroup" />,
				<Ref Func="GapsOfNumericalSemigroup" />,
				<Ref Func="FrobeniusNumberOfNumericalSemigroup" /> and
				<Ref Func="MinimalPresentationOfNumericalSemigroup" />.
				Finally, it is also possible to add functions to this list and remove them.
                <Example><![CDATA[
gap> s:=RandomNumericalSemigroup(3,9);
<Numerical semigroup with 3 generators>
gap> XNumericalSemigroup(s);
]]></Example>

	This would pop up the following window:
	<P/>
	<Alt Only="LaTeX">
		\begin{figure}[htbp] \begin{center} \leavevmode \includegraphics{xnumsgp} \end{center} \label{fig:xnumsgp} \end{figure}
	</Alt>
	<Alt Only="HTML">
		&#60;br&#62;&#60;center&#62;&#60;img src=&#34;xnumsgp.png&#34;&#62;&#60;/center&#62;&#60;br&#62;
    </Alt>
	<P/>
            </Description>
        </ManSection>



</Section>

</Appendix>