Re: Limit[f[x], x->a] vs. f[a]. When are they equal?
- To: mathgroup at smc.vnet.net
- Subject: [mg118442] Re: Limit[f[x], x->a] vs. f[a]. When are they equal?
- From: Richard Fateman <fateman at cs.berkeley.edu>
- Date: Thu, 28 Apr 2011 06:35:39 -0400 (EDT)
- References: <ip6834$bmt$1@smc.vnet.net>
On 4/26/2011 3:51 AM, Andrzej Kozlowski wrote: .. skipped and snipped... > and so on. In Mathematica is no sense in taking limits as z ->ComplexInfinity > without specifying a direction as there is no natural direction. So the idea of a limit as x->x0 makes no sense if x0 is a member of some set of numbers, symbols, whatever. Maybe the documentation for Limit should provide some information on this? I don't know what you have written previously on this topic and have no intention of looking it up. But in a system which includes ComplexInfinity, a concept which unifies at one "place" positive real infinity and negative real infinity, it becomes tricky to also have the separate values +Infinity and -Infinity. some of my thoughts are in section 4 of http://www.cs.berkeley.edu/~fateman/papers/interval.pdf RJF