[lojban-beginners] Re: order of sumti effects their meaning?

[Luke Bergen <lukeabergen@gmail.com>]

I guess where I'm confused is this:

5.5)  de poi gerku cu batci
        ro da poi prenu
    There-is-a-Y which is-a-dog which-bites
        every Y which is-a-person
    Some dog bites everyone.

5.6)  ro da poi prenu cu se batci
        de poi gerku
    Every-X which is-a-person is-bitten-by some-Y
        which is-a-dog.


So, in 5.5 "de poi gerku" equates to "some single thing which is a dog" but in 5.6 it's "some thing which is a dog".  Why?  When you quantify a variable does that automatically make all following variables in terms of it?


 - Luke Bergen

On Sat, Apr 18, 2009 at 5:55 PM, Robin Lee Powell <rlpowell@digitalkingdom.org> wrote:

On Sat, Apr 18, 2009 at 05:35:23PM -0400, Luke Bergen wrote:
> so I just read through section 5 of chapter16 of the refgram and
> am confused by this line:  "since it is the order in which the
> variables appear that matters we can say ...".
>
> basically in "de poi gerku cu batci ro da poi prenu"  "de poi
> gerku" is translated as "there-is-a-Y which is a dog"  but in "ro
> da poi prenu cu se batci de poi gerku" the same string is
> translated as "_some_ Y which is a dog".

Those mean exactly the some thing, AFAICT.  What makes you think
they are different?

The order matters because we stole this construct from predicate
logic; understanding that is really required to understand these
sentences.  The issue is binding of numbers on the variables.  In
the first sentence, there is 1 de, some dog.  It bites every human;
many da.  That is, the single de scopes over the many da.  "There is
a (single) dog which bit every human".

In the second sentence, there are many da, but they scope over the
single de, which means that there is a single de *for each of the
many humans*.  "Every human is bitten by a dog (but they need not
all be the same dog)".

*Technically*, da/de with no number is "su'o da", so the
hyper-explicit versions are:

"There exists at least one particular dog(s) which, by themself/ves,
bit every human."

"For every human, there exists at least one particular dog(s) which
bit him/her."

The issue is order of quantification, not order of variables as
such.  You can make the first sentence into the second by doing:

ro da de zo'u de poi gerku cu batci ro da poi prenu

This puts the specification of quantifier scoping out front, to make
it more explicit that we've got predicate logic scoping and weird
shit may occur.

-Robin

--
They say:  "The first AIs will be built by the military as weapons."
And I'm thinking:  "Does it even occur to you to try for something
other than the default outcome?" -- http://shorl.com/tydruhedufogre
http://www.digitalkingdom.org/~rlpowell/ *** http://www.lojban.org/