# [Maxima] assume behavior

Stefano Ferri ferriste at gmail.com
Thu Oct 8 11:36:15 CDT 2009

```Maxima says that it is unknown because your expression %i2 is assumed
not to contain the equality to 0.
I have not Maxima here to try, but if you enter

is(a - d + x > =0)

you should now get false as an answer.

Stefano

2009/10/8 TP <paratribulations at free.fr>:
> Hi everybody,
>
> I begin with Maxima. I do not understand the behavior of "assume". Test the
> following commands:
>
> /**********/
> assume ( d>x+a );
>
> is( x-d+a < 0 );
> is( x-d+a > 0 );
> /***********/
>
> I obtain:
>
> (%i2)                          assume(d > a + x)
> (%o2)                          [- x + d - a > 0]
> (%i3)                          is(a - d + x < 0)
> (%o3)                                true
> (%i4)                          is(a - d + x > 0)
> (%o4)                               unknown
>
> Shouldn't it be "false" instead of "unknown"? I must miss something.
>
> Thanks in advance,
>
> Julien
>
> --
> python -c "print ''.join([chr(154 - ord(c)) for c in '*9(9&(18%.\
> 9&1+,\'Z4(55l4('])"
>
> "When a distinguished but elderly scientist states that something is
> possible, he is almost certainly right. When he states that something is
> impossible, he is very probably wrong." (first law of AC Clarke)
>
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>

```

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