Subject: Re: [lojban] Bald men

From: "James F. Carter" <[email-masked]>
Date: Wed, 31 Oct 2001 11:48:02 -0800 (PST)

I didn't notice that this question actually got answered.

On Sun, 28 Oct 2001, Invent Yourself wrote:
> The naku Wiki page says the following. Is it true?

jimc says: No.

> "All men don't have hair" can be represented in Lojban as
> ro nanmu na se kerfa

As pc points out, English speakers could interpret the sentence two ways:
"each and every man doesn't have hair", or "it's not true that every man
has hair". A logician would pick the first one, Lojban is a logical
language, and the Lojban text is constructed accordingly.

> which prenexes as
> naku ro da poi nanmu zo'u kerfa da

No, it doesn't. The author hoped for the second interpretation, but has
failed to use De Morgan's rules when re-ordering a negated sentence:
exchange "and" vs. "or", and likewise exchange existential vs. universal
quantification.

> It is false that for each X that is a man, (something) is X's hair
> which is true: some men are bald.

Here's my rendition:

naku *su'o* da poi nanmu zo'u kerfa da
It's false that for even one X which is a man, there exists
Y [which is] the hair of X.
All men are bald.

James F. Carter Voice 310 825 2897 FAX 310 206 6673
UCLA-Mathnet; 6115 MSA; 405 Hilgard Ave.; Los Angeles, CA, USA 90095-1555
Email: [email-masked] http://www.math.ucla.edu/~jimc (q.v. for PGP key)