Updated answer, Re: [sc34wg3] TMRM v6.0 comments
Wed, 27 Jul 2005 06:51:09 -0400
Nikita Ogievetsky wrote:
>Thank you, - how did not I see "l" :-)
Err, because formal notation is more precise than English? ;-) Had I
tried to say the same thing in English, the error would have been obvious.
>However, I still have hard time with these formulas: (9) and (10).
>It is not clear what is the significance of the result, what did we try to
>prove? It is also not clear how did we arrive from (9) to (10).
>In any case if it is correct, it means that the product between two tuple
>sequences (or ordered sets :-)) is not a symmetrical operation, which I
>really doubt. May be I am just missing something very obvious.
>I would greatly appreciate if you or Robert could help clarify this
I would have to ask Robert to be sure but it appears to me that there
are two separate tuple sequences, I assume a tuple sequence of keys and
a tuple sequence of values. Since all the operations described thus far
return tuples and sequences of tuples, the keys and values have to be
stitched back together.
Recall that earlier the statement is made: "All tuples in a tuple
sequence must have the same number of values."
That is only possible because the tuple sequence is the result of a
*path expression* being applied to a set of subject proxies.
In other words, just like an SQL expression, you are either going to get
a value or NULL for everything asked for in the expression. So, the all
the tuples in a tuple sequence will always have the same number of
values by definition.
Everything in section 4 depends upon that premise that we are working on
the result of a path expression.
Hope you are having a great day!
PS: More replies after I get to Montreal later today. I have to finish
>! -----Original Message-----
>! From: firstname.lastname@example.org [mailto:sc34wg3-
>! email@example.com] On Behalf Of Patrick Durusau
>! Sent: Tuesday, July 26, 2005 10:23 AM
>! To: firstname.lastname@example.org
>! Subject: Updated answer, Re: [sc34wg3] TMRM v6.0 comments
>! An updated answer to your third question:
>! Nikita Ogievetsky wrote:
>! > Dear Steve, Patrick, Robert, and all,
>! > 3) It is not clear what is in (.) between (v1j, v2j,.,v1j) in
>! > expression (9) on p11
>! Actually not a typo, just poor editorial practice.
>! Using capital letters will make it plain:
>! (v1j, v2j,...,vLj)
>! The text uses a lower case "L" in the last term, which with a fairly
>! good magnifying glass is different from the number "1" in the subscript
>! for v at the beginning of the sequence.
>! Same is true for the second sequence in that equation.
>! That also happens in expression (12) on page 12, expressions (18), (19),
>! and (20), on page 13, and expression (21) on page 14.
>! Note that p_m is used in (13) on page 12, despite P_M being defined as
>! the set of all path expressions. In (13) it simply marks the last in a
>! sequence of path expressions.
>! The usage of p_m is also inconsistent with p_n which you will find in
>! 4.2, condition #3.
>! There are others I am sure I have not noticed yet so please feel free to
>! point them out. Consistency and good editorial practice (like not using
>! graphically similar characters to mean different things) would go a long
>! way to making the formalism easier to read.
>! Sorry 'bout that!
>! Hope you are having a great day!
>! Patrick Durusau
>! Chair, V1 - Text Processing: Office and Publishing Systems Interface
>! Co-Editor, ISO 13250, Topic Maps -- Reference Model
>! Member, Text Encoding Initiative Board of Directors, 2003-2005
>! Topic Maps: Human, not artificial, intelligence at work!
>! sc34wg3 mailing list
>sc34wg3 mailing list
Chair, V1 - Text Processing: Office and Publishing Systems Interface
Co-Editor, ISO 13250, Topic Maps -- Reference Model
Member, Text Encoding Initiative Board of Directors, 2003-2005
Topic Maps: Human, not artificial, intelligence at work!