From: ram@zedat.fu-berlin.de   
      
   William Hyde  wrote or quoted:   
   >"A continuous function is one whose inverse maps open sets to open sets"   
      
     It might be better to ask that the preimages of open sets come   
     out open, because if you think about the sine function, you   
     can still use that test on it even though it does not have an   
     inverse, since that wouldn't be single-valued.   
      
     (I'm not too sure about this, but that's just what came to mind.)   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)