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Re: All hail Neo!

From: Marshall Spight <marshall.spight_at_gmail.com>
Date: 30 Apr 2006 20:39:37 -0700
Message-ID: <1146454777.705589.76860@j33g2000cwa.googlegroups.com>


Jay Dee wrote:
> Marshall Spight wrote:
> > Jay Dee wrote:
> >
> >>Marshall Spight wrote:
> >>
> >>>Bob Badour wrote:
> >>>
> >>>
> >>>>If one starts with a two valued logic and adds a third value, one
> >>>>changes all of the features of the prior logic. Every truth table must
> >>>>change. Every identity is potentially affected as are associativity,
> >>>>distributivity etc.
> >>>
> >>>Do the pre-existing rows of the truth tables of existing
> >>>boolean functions change?
> >>
> >>Yes; columns and rows are added. The result is the "combinatorial
> >>explosion" referred to elsewhere.
> >
> >
> > Columns are added to the truth tables of existing boolean functions,
> > you say? Can you give an example? The columns of the truth table
> > for a boolean function correspond to the input and output parameters
> > of that function, so saying column are added is saying that there
> > are additional arguments or result values. This is certainly not
> > true for AND and OR; can you give an example of a boolean function
> > for which it is true?
> >
> > And the assertion that "rows are added" does not make
> > a "yes" answer to my question. Adding rows does not
> > change the pre-existing rows.
> >
> > I know what the combinatorial explosion is, and it's one reason
> > why I argue against the use of 3VL in language design.
> >
> >
> > Marshall
> >
>
>
> (using a monospace font...)
>
> and| T | F
> ---+-------
> T | T | F
> F | F | F
>
> must become
>
> and| T | F | null
> ----+-------------
> T | T | F | ?
> F | F | F | ?
> null| ? | ? | ?
>
> more columns, more rows.

Ah, I see. You are using a structure for the truth table where each axis is a parameter. That is perfectly valid, but it is not how I structure them, so we are talking past each other.

I prefer all the parameters (in and out both) as columns; it generalizes better to n-ary functions.

Anyway, it appears we all agree "NVL bad".

Marshall Received on Sun Apr 30 2006 - 22:39:37 CDT

Original text of this message

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