MaplePrimes - comments on Post, infinity and properties

MaplePrimes - comments on Post, infinity and properties http://www.mapleprimes.com/posts/38700-Infinity-And-Properties en-us 2026 Maplesoft, A Division of Waterloo Maple Inc. Maplesoft Document System Fri, 12 Jun 2026 18:24:41 GMT Fri, 12 Jun 2026 18:24:41 GMT The latest comments added to the Post, infinity and properties http://www.mapleprimes.com/images/mapleprimeswhite.jpg MaplePrimes - comments on Post, infinity and properties http://www.mapleprimes.com/posts/38700-Infinity-And-Properties what is real http://www.mapleprimes.com/posts/38700-Infinity-And-Properties?ref=Feed:MaplePrimes:infinity and properties:Comments#comment69790 From these: <pre> RealRange(-infinity,infinity); real RealRange(Open(-infinity),Open(infinity)); real </pre> I think that the first is wrong. I do not find consistent either that something called 'realcons' include infinity. The latest comments added to the Post, infinity and properties 69790 Fri, 12 Sep 2008 02:08:19 Z jakubi jakubi open and closed http://www.mapleprimes.com/posts/38700-Infinity-And-Properties?ref=Feed:MaplePrimes:infinity and properties:Comments#comment69789 I see what is unsettling, but I can see a couple of ways to argue that Maple's response is not absurd. For example, RealRange(-infinity,infinity) could be understood to be the set of real numbers x such that -infinity<= x and x<= infinity. Since infinity is not a real number, RealRange(-infinity,infinity) is equal to RealRange(Open(-infinity),Open(infinity)). Another tack is to realize that topologically, R is simultaneously an open interval and a closed interval. The latest comments added to the Post, infinity and properties 69789 Fri, 12 Sep 2008 02:45:40 Z Alex Smith Alex Smith not so sure http://www.mapleprimes.com/posts/38700-Infinity-And-Properties?ref=Feed:MaplePrimes:infinity and properties:Comments#comment82869 I understand the topology viewpoint. But I am not happy with the mixed results. Neither am I thrilled with this: <pre> > is( abs(x) < infinity ); true </pre> acer The latest comments added to the Post, infinity and properties 82869 Fri, 12 Sep 2008 03:36:45 Z acer acer others http://www.mapleprimes.com/posts/38700-Infinity-And-Properties?ref=Feed:MaplePrimes:infinity and properties:Comments#comment69788 Others that I find strange, <pre> > assume(x=3); > is(x<4); # ok true > is(x<3); # ok false > assume(x=infinity); > is(abs(x)<infinity); true > assume(x>=infinity); Error, (in assume) the assumed property or properties cannot be satisfied </pre> acer The latest comments added to the Post, infinity and properties 69788 Fri, 12 Sep 2008 03:44:15 Z acer acer Since infinity is not a real number http://www.mapleprimes.com/posts/38700-Infinity-And-Properties?ref=Feed:MaplePrimes:infinity and properties:Comments#comment82868 the intersection ('AndProp') of properties 'real' and 'infinity' should be "empty", ie 'BottomProp', but: <pre> AndProp(real,infinity); AndProp(real, infinity) </pre>   The latest comments added to the Post, infinity and properties 82868 Fri, 12 Sep 2008 04:07:36 Z jakubi jakubi Since infinity is not a real number http://www.mapleprimes.com/posts/38700-Infinity-And-Properties?ref=Feed:MaplePrimes:infinity and properties:Comments#comment82867 the intersection ('AndProp') of properties 'real' and 'infinity' should be "empty", ie 'BottomProp', but: <pre> AndProp(real,infinity); AndProp(real, infinity) </pre>   The latest comments added to the Post, infinity and properties 82867 Fri, 12 Sep 2008 04:37:56 Z jakubi jakubi