\centerline{ \beginpicture \setcoordinatesystem units <1mm,1mm> \setlinear % \setdots <1mm> \setlinear \plot 0 0 60 20 / \put {$\bullet$} at 0 0 \put {$A_1$} [rt] at -1 0 \put {$\bullet$} at 60 20 \put {$E_n$} [lt] at 61 20 \setquadratic \plot 0 0 30 20 60 20 / \setlinear \plot 30 10 30 16 / \put {$\epsilon$} [rb] at 29 11 \setdots \plot 0 6 60 26 / % \endpicture }