wdh@linus.UUCP (W. Dale Hall) (02/08/90)
In article <1990Jan29.163009.14547@cs.rochester.edu> fulk@cs.rochester.edu (Mark Fulk) writes: > >2) d(x,y) >= 0; d(x,x) = 0; d(x,z) >= d(x,y) + d(y,z). > Applies to lots of spaces, e.g. the real line. > I'm having trouble with this one. To me, it certainly seems that d(4,5) < d(4,-1000) + d(-1000,5) That's the only example I could come up with, but it seems to be sufficient to disprove the inequality d(x,z) >= d(x,y) + d(y,z) given above. That's all I know for now. Dale.