Message-ID: <3496E6B0.B41@locke.ccil.org>
Date: Tue, 16 Dec 1997 15:38:08 -0500
From: John Cowan <cowan@locke.ccil.org>
Organization: Lojban Peripheral
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To: Lojban List <lojban@cuvmb.cc.columbia.edu>
Subject: Re: xor questions (was Re: indirect Qs (was Re: On logji lojbo discu
References: <199712161743.MAA16599@locke.ccil.org>
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la .and. cusku di'e

>   ke`a tcati                   T T F F
>   ke`a ckafi                   T F T F
>   ke`a go tcati gi ckafi       T F F T
>   ke`a na go tcati gi ckafi    F T T F
> 
> If {ke`a na go tcati gi ckafi} means something else, what does
> it mean?

Your truth-table is correct.

> What does {gonai} mean?

It means go naku ... gi ..., which happens to have the same
truth table:  FTTF.  But this works because O is a symmetrical
truth function.  For inclusive-or, we get:

	A			T T F F
	B			T F T F
	ga A gi B		T T T F (either A or B or both)
	na ga A gi B		F F F T (neither A nor B)
	ganai A gi B		T F T T (if A then B)
	ga A ginai B		T T F T (A if B)

> > But is that really what we want to ask? An unhelpful answer like
> > {lo selpinxe} or {lo glare} would make the bridi true. (Same thing
> > happens with your other versions.)
> 
> If {ma} really does mean "replace this word with another than
> makes the bridi true", then this problem does exist.

It exists, but so what?  Any questioner has to allow for the
possibility of unhelpful (evasive, obscure, frame-breaking) answers.

-- 
John Cowan	http://www.ccil.org/~cowan		cowan@ccil.org
			e'osai ko sarji la lojban