\begin{figure}[H] \begin{center} \unitlength=4pt \begin{picture}(25, 14)(0,-4) \gasset{Nw=5,Nh=5,Nmr=2.5,curvedepth=3} \thinlines \node[Nmarks=if,iangle=180,fangle=180](A1)(0,0){$1$} \node(A3)(25,0){$3$} \drawloop[loopangle=90](A1){$a^2+b^2$} \drawloop[loopangle=90](A3){$a^2+b^2$} \gasset{curvedepth=4} \drawedge(A1,A3){$ab+ba$} \drawedge(A3,A1){$ab+ba$} \end{picture} \end{center} \caption{Après élimination de l'état $4$.} \end{figure} |