# Re: cdt glossary 0.1.0 [Relation]

From: dawn <dawnwolthuis_at_gmail.com>
Date: 25 Feb 2006 05:20:12 -0800

Mark Johnson wrote:
> [Relation]
> 1. A relation is a subset of the set of ordered
> tuples (A1, A2, ... Am) formed by the Cartesian
> cross-product of sets S1 x ... x Sm where each
> An is an element of Sn.
>
> I might say, instead, because I think they logically go closely
> together, and again just as a suggestion, nothing more:

> Relation - mathematically by a language of sets, a relation is an
> (ordered) array/tuple of elements drawn one each from a set of
> domains, in order, with duplicate domains allowed. This set of
> n-tuples, said to have degree, n, or to be 'n-ary', where the number
> of n-tuples is said to be its, cardinality. The relation is uniquely
> named with regard to other relations. It can both be imagined and
> represented as a 2-D grid, or table.

> Tuple - also termed an, element, of a relation, it is an unordered set
> of n-attributes,

Once I was able to read it that way, I could better identify whether I agreed or disagreed with it. In this case, I disagree. 1. A tuple is not a set. 2. I don't know what an n-attribute is. 3. Tuples are not unordered. The combination of poor grammar and punctuation along with imprecise terminology makes it very difficult for me to read, and I am a native speaker of English. There a many readers where English is a second language and I'm sure this makes it very difficult for them to understand you too.

> each attribute drawn from a particular dimension or
> domain, as irreducible 'atomic' scalars or strings (though multiples,
> if a multi-valued domain, were once considered),

> and identified by
> unique name in order to a) express any relationship among any set of
> attributes and b) to allow the tuple to have no particular order. As
> an unordered tuple does not properly correspond with a set relation,
> the relation might be termed, instead, a relationship, which might
> more properly correspond with a table. The tuple can be imagined as a
> vector/array. The tuple can be imagined and represented as a rows in
> the table, its attributes as columns.

I think you have points you are trying to make and also seem to have familiarity with the topics, but in all of the postings of yours that I have read, I am unable to determine what your points are. I see that you have not taken kindly to suggestions to improve your writing style so that we can better undersand you, but I agree with those who have made such suggestions. I'll try to read your next few postings, but if I am still unable to understand, I'll have to pass in the future. I make a ton of typos in my writing here and have a problem writing too much when I don't edit myself, so I understand you might be moving fast.

My specific suggestions, in case you find them helpful, are to

```a) improve your use of commas, primarily by removing many
b) verify that each sentence is a sentence
c) use the terms already in the glossary according to the definitions
```
given there (at least as an exercise to help improve readability for now),
d) Use other terms as precisely as feasible, particularly if you are trying to provide a definition or description for a term e) proofread and edit at least your next few posts (I need to do this more often too).

I think many of your readers will try to meet you half-way if you can help us better understand what you are trying to tell us. Best wishes.  --dawn Received on Sat Feb 25 2006 - 14:20:12 CET

Original text of this message