       Re: Logical Expression

• To: mathgroup at smc.vnet.net
• Subject: [mg73442] Re: [mg73385] Logical Expression
• From: "Chris Chiasson" <chris at chiasson.name>
• Date: Fri, 16 Feb 2007 01:07:32 -0500 (EST)
• References: <200702150956.EAA04579@smc.vnet.net>

```The special characters in your email are garbled, which is possibly
due to improper character encoding.

Anyway, try playing with

Experimental`\$SameQTolerance

and

Experimental`\$EqualTolerance

, which are described in the help browser, I believe. The inequality
functions (< <= > >= ) use the SameQ tolerance, while the equality
function ( == ) uses the Equal tolerance. You can use SameQ ( === )
instead of Equal ( == ).

On 2/15/07, Martin Schoenecker <ms_usenet at gmx.de> wrote:
> Common sense tells me that the statement that "something is equal to
> zero, and unequal to zero at the same time" is a false statement:
>
> In:= a == 0 && a != 0
> Out= a\[Equal]0&&a=E2=89=A00
>
> In:= LogicalExpand[%]
> Out= False
>
> The same, in my opinion, applies to "something is equal to zero and
> greater than zero at the same time".  Why doesn't Mathematica think so,
> and how to convince it to evaluate the following?
>
> In:= a == 0 && a > 0
> Out= a\[Equal]0&&a>0
>
> In:= LogicalExpand[%]
> Out= a\[Equal]0&&a>0
>
>
> Martin
>
>

--
http://chris.chiasson.name/

```

• Prev by Date: Dll problem
• Next by Date: Re: Logical Expression
• Previous by thread: Re: Logical Expression
• Next by thread: Re: Logical Expression