[Maxima-bugs] [ maxima-Bugs-1726550 ] not bugs

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Bugs item #1726550, was opened at 2007-05-27 18:01
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Category: Lisp Core - Simplification
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Barton Willis (willisbl)
Assigned to: Robert Dodier (robert_dodier)
Summary: not bugs

Initial Comment:
(1) not signals an error for a CRE argument:

(%i1) not(rat(x));
Maxima encountered a Lisp error:

(2) not allows more than one argument:

(%i2) not(a,b);
(%o2) not b

(3) not signals an error for a subscripted function
argument

(%i3) not(f[1](x));
Maxima encountered a Lisp error:
 Error in PROGN [or a callee]: Bad plist ((1 DATA
                                           (((MGRP

(4) not signals an error for a taylor poly argument:

(%i14) not(taylor(x,x,0,5));
Maxima encountered a Lisp error:


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Comment By: Rafael Cantero (srci)
Date: 2007-12-12 20:34

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About (2):

"The logical negation operator. not is a prefix operator; its operand is a
Boolean expression, and its result is a Boolean value. 

not forces evaluation (like is) of its operand. " (from Maxima manual)

in other words:
- not is not a function. Parenthesized list return last argument:

not (a,b) must give not b



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Comment By: Barton Willis (willisbl)
Date: 2007-05-27 23:05

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'and' and 'or' have similar problems: try

   f[1](x) and p,  x or rat(x), taylor(x,x,0,2) and p, ...





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Comment By: Barton Willis (willisbl)
Date: 2007-05-27 18:07

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One more:

(%i1) not(a >= b);
(%o1) a<b
(%i2) tellsimp(a < b, true);
(%o2) [<rule1,false]
(%i3) not(a >= b);
(%o3) a<b
(%i4) expand(%,0,0);
(%o4) true

(%o3) isn't simplified.

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