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Topic: Multiplication by 0: non-zero in versions 8 and 9
Replies: 2   Last Post: Jun 17, 2013 6:20 AM

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 Richard Fateman Posts: 1,539 Registered: 12/7/04
Re: Multiplication by 0: non-zero in versions 8 and 9
Posted: Jun 16, 2013 5:09 AM

On 6/15/2013 1:16 AM, Sotirios Bonanos wrote:
> Hello ,
>
> I have noticed that in all Mathematica versions <8, multiplying a
> real or complex number by the integer 0 gives 0, but in versions 8
> and 9
>
> Times[0, 0.567] gives 0.
>
> and
>
> Times[1.23 + I 2.45, 0] gives 0. + 0. I
>
> I don't know what prompted this change but it is definitely wrong:
> the zero property of multiplication holds for real and complex
> numbers also (see
> https://en.wikipedia.org/wiki/Multiplication#Properties) .
>
> Sotirios Bonanos http://www.inp.demokritos.gr/~sbonano/
>
>

You appear to be making a distinction between "0" and "0."
and "0.+0.I". Yet for Mathematica, 0==0.+0.*I returns True.

You may have a valid objection to something that has been
changed in the program, but appealing to the wikipedia
article is not particularly significant.

After all,
Times[0,x] comes out as 0, but this is not what happens
for x being 0., Indeterminate, Infinity, Interval[{-1,1}],
and probably other stuff.

As Dorothy said, you are not in Kansas anymore.
http://en.wiktionary.org/wiki/not_in_Kansas_anymore

Date Subject Author
6/15/13 sbonano@inp.demokritos.gr
6/16/13 Richard Fateman
6/17/13 Daniel Lichtblau