Message-Id: <199601071326.IAA22736@locke.ccil.org>
Date:         Sun, 7 Jan 1996 13:01:28 +0000
Reply-To: ucleaar <ucleaar@UCL.AC.UK>
Sender: Lojban list <LOJBAN@CUVMB.BITNET>
From: ucleaar <ucleaar@UCL.AC.UK>
Subject:      tech:logic matters
To:         lojban@cuvmb.cc.columbia.edu
Status: OR
Content-Length: 1503

pc:
> &
> Okay. So {ro da broda} entails {da broda}. But all other uses of {ro}
> don't entail existence - {ro da poi kea broda cu brode} and
> {ro broda cu brode} entail neither {da broda} nor {da brode}.
> One ought to be encouraged, I think, to not use poi clauses with da,
> and to instead use logical connectives.
> pc:
> Well, in fact, _ro da poi broda_ was introduced ages ago exactly to
> carry the implication that there are brodas.

I'm especially out of my depth here, so forgive my being slow on the
uptake. I hope I'm right in thinking that "Ax: F(x) -> G(x)" does not
entail "Ex F(x)" (or "Ex G(x)"). [I understand from you that it does
entail "Ex: F(x) -> G(x)".]

I have thought that {ro da poi kea broda cu brode} and {ro broda cu
brode} both give "Ax: broda(x) -> brode(x)" - with neither entailing
"Ex broda(x)". I assumed that it is in emulation of nat lang syntax
rather than predicate logic that these forms are used in preference to a
form with logical connectives (ganai...gi).

> The other expressions, _ro broda_ and _ro lo broda_ are, I think, up
> for grabs, but Cowan sems to have appropriated all of these distinct
> expressions for some other set of distinctions. And I, of course,
> think that _ro_ should be treated as uniformly as possible, which
> would mean requiring the _ganai _gi_ construction to get the "modern"
> interpretation.

It would be helpful if you would indicate what logical form corresponds
to {ro da poi kea broda} and {ro broda}.

coo; mie lao a &