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Education > Algebra help > Re: Algebra Que...
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Re: Algebra Questions

by Paul Sperry <plsperry@[EMAIL PROTECTED] > May 14, 2008 at 03:53 AM

In article <pafWj.134$Pp2.31@[EMAIL PROTECTED]
>, Jack <jj@[EMAIL PROTECTED]
>
wrote:

> > Do you mean _factors_ of a?
> 
> No, I meant *multiples* of a(m). Or a(J) when I am using the subset of
m, J. 
> The product of all primes in J is a column in which there are J entries.

> Same with the column indexed by twice the product, etc. The fact that
these 
> columns are found exclusively at intervals of a(m)+1 is the reason I
want 
> one such at the column indexed by zero.

What we have here is a failure to communicate.

You started with
>>Take x and y to be integers.
>>If we have a set P(m) comprising the first m primes and a
>>general subset J of of P(m), then I am constructing a matrix M_1 in
>>which the members of J index the rows. Let the columns number f. 
>>Let p be a 
>>member of J. The matrix components, of which in any subinterval 
>>[x,y] of 
>>[0,f-1], there are (y-x+1)*J, are either occupied or unoccupied. 
>>If n is an 
>>integer indexing a column, the occupied matrix components are 
>>given by 
>>(p|n), save for zero which contains #J occupied matrix components. The
>>number of occupied matrix components in the n-th column is given by 
>>g(n,M_1).
>>
>>I am also constructing an array M_[x,y] comprising black cells and
>>white cells. The number of black cells in a column is given by
>>t(n,M_[x,y]). My question is, will it be acceptable in a 
>>mathematical paper 
>>to devise a form of notation referencing an interval [x,y] in 
>>such a way 
>>that the values of t(n,M_[x,y]) over [x,y] are precisely those 
>>given by 
>>g(n,M_1) for an interval [x,y] in M_1? (i.e. if u divides v, 
>>and u is a 
>>member of J, then there is a single black cell on the u-th row 
>>and in the 
>>v-th column. Otherwise, there is none such, save in the 
>>column indexed by zero.)

I eventually proposed
>Let P(m) be the m-th prime and let p(1) < p(2) < ... < p(t) <= P(m) be
>primes.
>Let f be an integer and let 1 <= x(1) < x(2) < ... x(r) <= f be
>integers and let M(x,y) be a t by r matrix. The (i, j) entry of M(x,y)
>is said to be "occupied" if p(i) divides x(j); otherwise, the entry is
>"unoccupied".

And then
> If ones and zeros are OK with you then the definition of M becomes
> cleaner: M_(i,j) = 1 if p(i) divides x(j) and M_(i,j) = 0 otherwise.

Which you seemed to like.

I even gave an example
>Let J be a sequence of primes p(1) < p(2) < ... < p(t);
>Let C be a sequence of integers x(1) < x(2) < ... < x(r).
>Define M(J,C) [i.e M_1] to be the t x r matrix whose (i,j) entry is 1
if p(i)
>divides x(j) and is 0 otherwise.
>
>For example let J be 2, 5, 11 let C be 4, 15, 16, 22 then M(J,C) is
>1  0  1  1
>0  1  0  0
>0  0  0  1.

Which you didn't object to.

_Now_ you say
>>No, I meant *multiples* of a(m) [the product of the first m primes].
>>Or a(J) when I am using the subset of [P(m)], J. 
>>The product of all primes in J is a column in which there are 
>> entries. 
>>Same with the column indexed by twice the product, etc. The fact 
>>that these 
>>columns are found exclusively at intervals of [a(m)] is the 
>>reason I want 
>>one such at the column indexed by zero.

Well, I'm lost. How does this conform to your previous definition of
M_1? For that matter what do you mean by "The product of all primes in
J is a column in which there are J entries"?

In an effort to clear things up I asked for an example. I _still_ would
like to see an example with actual numbers and matrices/arrays. 

You still haven't said what you mean by "array" - it is not a commonly
used mathematical term.

I have a vague hunch that what you want is something like what
_programmers_ call an array of arrays. 

Here's an example - the numbers have nothing to do with your problem.
It is sort of suggested by your mention of "histogram".

A := [U, V, W, X]
U := [1, 2, 3]
V := [4, 5, 6, 7]
W := [8, 9]
X := [ 10, 11, 12]

A is an array (of arrays); U, V, W and X are arrays.

A[0] = U; A[2] = W; A[2][1] = A[2, 1] = W[1] = 9.

Schematically (row dominant) A is

1   2   3
4   5   6   7
8   9
10  11  12

-- 
Paul Sperry
Columbia, SC (USA)
 




 42 Posts in Topic:
Algebra Questions
"Jack" <jj@[  2008-05-03 13:27:14 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-04 02:48:30 
Re: Algebra Questions
"Jack" <jj@[  2008-05-04 12:42:47 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-04 19:09:02 
Re: Algebra Questions
"Jack" <jj@[  2008-05-05 00:51:40 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-05 04:54:53 
Re: Algebra Questions
"Jack" <jj@[  2008-05-05 13:28:54 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-06 18:57:27 
Re: Algebra Questions
"Brian M. Scott"  2008-05-06 15:04:40 
Re: Algebra Questions
"Jack" <jj@[  2008-05-07 12:25:21 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-09 03:40:13 
Re: Algebra Questions
"Jack" <jj@[  2008-05-09 13:11:46 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-11 06:30:54 
Re: Algebra Questions
"Jack" <jj@[  2008-05-12 13:07:31 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-13 07:04:06 
Re: Algebra Questions
"Jack" <jj@[  2008-05-13 12:06:22 
Re: Algebra Questions
"Jack" <jj@[  2008-05-13 12:44:21 
Re: Algebra Questions
"Jack" <jj@[  2008-05-13 13:13:01 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-14 03:53:19 
Re: Algebra Questions
"Jack" <jj@[  2008-05-14 11:58:30 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-15 04:57:21 
Re: Algebra Questions
"Jack" <jj@[  2008-05-15 11:52:08 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-16 04:29:38 
Re: Algebra Questions
"Jack" <jj@[  2008-05-16 12:09:42 
Re: Algebra Questions
"Jack" <jj@[  2008-05-16 12:14:15 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-17 05:08:00 
Re: Algebra Questions
"Jack" <jj@[  2008-05-17 15:57:33 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-18 06:47:01 
Re: Algebra Questions
"Jack" <jj@[  2008-05-18 11:02:15 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-19 06:26:51 
Re: Algebra Questions
"Jack" <jj@[  2008-05-19 14:33:14 
Re: Algebra Questions (correction)
"Jack" <jj@[  2008-05-19 14:41:17 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-20 05:43:30 
Re: Algebra Questions
"Jack" <jj@[  2008-05-20 12:39:13 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-21 04:29:13 
Re: Algebra Questions
"Jack" <jj@[  2008-05-21 13:06:04 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-22 05:42:14 
Re: Algebra Questions
"Jack" <jj@[  2008-05-18 15:09:35 
Re: Algebra Questions
Paul Sperry <plsperry@  2008-05-19 06:35:54 
Re: Algebra Questions
"Jack" <jj@[  2008-05-29 15:36:55 
Re: Algebra Questions
"Jack" <jj@[  2008-05-12 13:36:21 
Re: Algebra Questions
"Jack" <jj@[  2008-05-12 14:08:00 

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tan12V112 Thu Dec 4 15:22:35 CST 2008.