Re: Types v. monadic relations

Date: Mon, 3 Feb 1992 13:33:35 PST
Subject: Re: Types v. monadic relations
To: macgregor@ISI.EDU
Cc:, interlingua@ISI.EDU
In-reply-to: Your message of Mon, 03 Feb 92 10:09:07 PST
Message-id: <>
> ...the semantic difference between` a "type" and a "monadic relation"?  
> Why should we care?

Good question. But apparently some people do, so why not allow predicates to
have a limited range of properties ( as in being-a-type-predicate ). The idea
is that unary second-order properties are legal in ground assertions, and
thats all. While that is technically second-order, this tiny a step towards
omega will not disturb anything important. For example, the unification
algorithm works just as before.  The alternatives seem to be (1) using a
different syntax for each style of predicate, as in current KIF, or (2)
allowing modalities, or something close. Neither of these is very attractive
either semantically or pragmatically.

Pat Hayes