Re: Infinity vs DirectedInfinity[1]
- To: mathgroup at smc.vnet.net
- Subject: [mg70562] Re: [mg70489] Infinity vs DirectedInfinity[1]
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Thu, 19 Oct 2006 03:23:37 -0400 (EDT)
- References: <200610180816.EAA07979@smc.vnet.net>
On 18 Oct 2006, at 17:16, Chris Chiasson wrote: > Infinity is a symbol, as far as I know. However, in FullForm it is > shown as the equivalent DirectedInfinity[1]. > > Is there some kind of MakeBoxes rule for FullForm that makes Infinity > show up that way? > > -- > http://chris.chiasson.name/ > In fact this is not quite true. Observe: In[1]:= FullForm[Hold[Infinity]] Out[1]//FullForm= Hold[Infinity] In[2]:= FullForm[Infinity] Out[2]//FullForm= DirectedInfinity[1] What happens is that the symbol Infinity evaluates to DirectedInfinity [1]. This kind of thing is not uncommon in Mathematica; e.g. 2+3 I evaluates to Complex[2,3] or 2/3 evaluates to Rational[2,3]. All this is purely Kernel stuff; no MakeBoxes involved. Andrzej Kozlowski Tokyo, Japan
- References:
- Infinity vs DirectedInfinity[1]
- From: "Chris Chiasson" <chris@chiasson.name>
- Infinity vs DirectedInfinity[1]