StevenXClontz’s avatarStevenXClontz’s Twitter Archive—№ 1,968

  1. …in reply to @Thalesdisciple
    @Thalesdisciple Many formulas about intervals which fail for points should probably be rewritten to say "open interval".
    1. …in reply to @StevenXClontz
      @Thalesdisciple er, TFW you notice @siwelwerd beat you to the same point. D-:
    2. …in reply to @StevenXClontz
      @Thalesdisciple e.g. the Cantor set contains no open intervals. Topologically this is better anyway: it's a nowhere dense set.
      1. …in reply to @StevenXClontz
        @Thalesdisciple e.g. if f is constant on an open interval, then f'=0 on that interval.
        1. …in reply to @StevenXClontz
          @Thalesdisciple Actually that fact is false for the endpoints anyway: the derivative could be 0 or undefined.