[lojban] Re: CFG prize challenge question

[Chris Capel <pdf23ds@gmail.com>]

On Wed, Feb 11, 2009 at 05:50, Jorge Llambías <jjllambias@gmail.com> wrote:
> On Wed, Feb 11, 2009 at 1:33 AM, Chris Capel <pdf23ds@gmail.com> wrote:
>> On Tue, Feb 10, 2009 at 11:23, Jorge Llambías <jjllambias@gmail.com> wrote:
>>>
>>> sentence = [terms [CU]] selbri [terms] /VAU/
>>>
>>> terms = [terms] sumti
>>>
>>> sumti = KOhA | LE selbri /KU/
>>>
>>> selbri = [selbri] tanru-unit
>>>
>>> tanru-unit = BRIVLA | NU sentence /KEI/
>>
>> So making 1=sentence, 2 = le, 3 = KOhA, 4 = nu, 5 = BRIVLA, the
>> allowable nestings (parent--child) would be 1--2, 1--3, 2--4, 2--5,
>> 4--1.
>
> Also: 1-4 and 1-5?

Ah, yes. Missed those.

> How can you tell for example that (1 (3 )3 (5 )5 (3 )3 )1 is valid but
> (1 (3 )3 (3 )3 )1 is not valid for this grammar? Is the set of valid
> phrases just given, in addition to the allowable nestings, at this
> point?

You can't. In this respect, the formalism falls short. I hope this
will not be considered to invalidate it for its intended, limited
purpose.

> How is the role of CU taken into account? It's presence/absence will
> play a role in whether a preceding )2 can be elided or not.

I think CU is more of an elidable "starter" than a terminator. You
could make bridi-tail a phrase type if you liked, to make the allowed
phrases closer to lojban, but you still wouldn't get the effects of
elision modeled properly. Once again, I think the formalism falls
short.

If I'm able to prove anything interesting with my current formalism, I
may try to generalize it some and prove or disprove those same
properties.

Chris Capel
-- 
"What is it like to be a bat? What is it like to bat a bee? What is it
like to be a bee being batted? What is it like to be a batted bee?"
-- The Mind's I (Hofstadter, Dennet)


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