453.jps

-4 5 setxrange
-1 1 setyrange
20 setxunit

traceOx

xticks
0 xtick
[0 1] {xmark} apply

/A{-2 0} def   
/B {xmax 0} def
/C{-2 -0.3} def   
/D{4.7 -0} def   
1.7 setlinewidth

[A B] (]-) ligne

%% definition du label

<tex>
$$
   +\infty
$$
</tex>

%% exemple 1 : simple

D dctexlabel 
  
setTimesItalic
   (a) C dctext