logical connective question from Mark S.

[Logical Language Group <cbmvax!uunet!GREBYN.COM!lojbab>]

Mark Shoulson asks:
>
>\juf sent 015
>\zoi se  mu'i    le  du'u          la         cev. na  zanru   lo    xlali
>\luj se  mu'i    le  du'u          la         ***  na  zanru   lo    xlali
>\gl  2nd because the the_sentence: that_named ***  not approve a/the bad
>
>\zoi valsi .a le  xlali _sel- ,zukte!
>\luj valsi .a le  xlali se    zukte
>\gl  word  or the bad   2nd   act
>
>The {.a} makes sense in English, but I'm not so sure in Lojban.  We need
>a conjunction paper pretty badly.  By the common method of expansion
>Colin often uses with devastating effect (devastating to those who
>misuse conjunctions), we get
>  {ga la cev. na zanru lo xlali valsi gi la cev. na zanru lo xlali selzukte}
>  "[either] 'god' doesn't approve-of bad-words, [or, and possibly both]
>  'god' doesn't approve of bad things-acted."
>
>Hmmm.  Doesn't seem quite right.  Colin, you're good at
>conjunctions, what do you think?

Nora answers:

The nature of "na" is such that you cannot distribute it like this.  You
must first move it up front (to the prenex) before using Colin's
expansion technique.  (See the negation paper for extensive examples and
explanation).  This gives:


\zoi se  mu'i    le  du'u          na  zo'u la         cev. zanru   lo    xlali
\gl  2nd because the the_sentence: not |    that_named ***  approve a/the bad

\zoi valsi .a le  xlali _sel- ,zukte!
\gl  word  or the bad   2nd   act

Or "It is false that (la cev. zanru A .a B)

This expands as predicted, but correctly to:


Or "It is false that (la cev. zanru A) .ija (la cev. zanru B)

This ends up working like DeMorgan's Rule


"It is false that la cev. zanru A, *and* it is false that la cev. zanru B."

This is what was wanted.

                                      co'omi'e.  noras.
----
Nora LeChevalier, Secretary/Treasurer, The Logical Language Group, Inc.
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