[Maxima] assume behavior

[TP]

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

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