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Re: Making 'eq' == 'eql' in bignum branch
From: |
Helmut Eller |
Subject: |
Re: Making 'eq' == 'eql' in bignum branch |
Date: |
Wed, 29 Aug 2018 07:40:56 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) |
On Wed, Aug 29 2018, Herring, Davis wrote:
> Of course +/-inf are numbers. They're not real numbers, but neither
> are complex numbers, split-complex numbers, dual numbers, p-adic
> numbers, quaternions, octonions, sedenions, hyperreal numbers, or
> (please no) surreal numbers. With all due respect to your
> mathematician friend, she has no exclusive claim over the definition
> (such as it is) of "number" (and I'm a bit surprised if she hadn't
> heard of at least one of the extended real lines I linked).
Also, it seems quite common to define max/min so that +/-inf are the
neutral elements <https://en.wikipedia.org/wiki/Identity_element>.
In Lisp, many associative operations return the neutral element if
called with zero arguments, e.g. (*) => 1. So I think it's quite nice
that (max) returns -infinity.
In Scheme, the syntax +inf.0 and -inf.0 is used for infinities. Emacs
Lisp could use the same as +inf.0 is just an ordinary symbol. At least
Schemers could remember that.
One could also write (/ 1 0.0) for +infinity; the easiest to remember
IMO.
Helmut
- Re: Making 'eq' == 'eql' in bignum branch, (continued)
- Re: Making 'eq' == 'eql' in bignum branch, Clément Pit-Claudel, 2018/08/29
- Re: Making 'eq' == 'eql' in bignum branch, Lars Ingebrigtsen, 2018/08/27
- Re: Making 'eq' == 'eql' in bignum branch, Pip Cet, 2018/08/27
- Re: Making 'eq' == 'eql' in bignum branch, Paul Eggert, 2018/08/27
- Re: Making 'eq' == 'eql' in bignum branch, Ken Raeburn, 2018/08/28
- Re: Making 'eq' == 'eql' in bignum branch, Helmut Eller, 2018/08/28
- Re: Making 'eq' == 'eql' in bignum branch, Stefan Monnier, 2018/08/28
- Re: Making 'eq' == 'eql' in bignum branch, Clément Pit-Claudel, 2018/08/28
- Re: Making 'eq' == 'eql' in bignum branch, Pip Cet, 2018/08/28
- Re: Making 'eq' == 'eql' in bignum branch, Herring, Davis, 2018/08/28
- Re: Making 'eq' == 'eql' in bignum branch,
Helmut Eller <=
- Re: Making 'eq' == 'eql' in bignum branch, Pip Cet, 2018/08/29
- Re: Making 'eq' == 'eql' in bignum branch, Alan Mackenzie, 2018/08/31
- Re: Making 'eq' == 'eql' in bignum branch, Clément Pit-Claudel, 2018/08/31
- Re: Making 'eq' == 'eql' in bignum branch, Alan Mackenzie, 2018/08/31
- Re: Making 'eq' == 'eql' in bignum branch, Herring, Davis, 2018/08/31
- Re: Making 'eq' == 'eql' in bignum branch, Stefan Monnier, 2018/08/31
- Re: Making 'eq' == 'eql' in bignum branch, Herring, Davis, 2018/08/31
- Re: Making 'eq' == 'eql' in bignum branch, Elias Mårtenson, 2018/08/28
- Re: Making 'eq' == 'eql' in bignum branch, Clément Pit-Claudel, 2018/08/29
- Re: Making 'eq' == 'eql' in bignum branch, Stefan Monnier, 2018/08/29