byrnema comments on Bizarre Illusions - Less Wrong

11 Post author: MrHen 27 January 2010 06:25PM

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Comment author: byrnema 28 January 2010 04:52:13PM *  2 points [-]

Information and expertise like this is why hanging out at Less Wrong is worth the time. I estimate that I value the information in your comment at about $35, meaning my present self would advise my former self to pay up to $35 to read it.

So, I get it. My brain is more wired for analysis than algebra; so this isn't the first time that linear algebra has been a useful bridge for me. I see that we could have a 'vector space' of infinite-dimensional vectors where each vector (a1, a2, ..., an, ...) represents a number N where N = (P1^a1)(P2^a2)...(Pn^an)... and Pi are the ordered primes. Clearly 1 is the zero element and would never be a basis element.

I should admit here that my background in algebra is weak and I have no idea how you would need to modify the notion of 'vector space' to make certain things line up. But I can already speculate on how the choice of the "scalar field" for specifying the a_i would have interesting consequences:

  • non-negative integer 'scalar field' --> the positive integers,
  • all integers 'scalar field' --> positive rational numbers,
  • complex integers --> finally include the negative rationals.

I'd like to read more. What sub-field of mathematics is this?

Comment author: Zack_M_Davis 08 February 2010 10:05:35AM 0 points [-]

I see that we could have a 'vector space' of infinite-dimensional vectors where each vector (a1, a2, ..., an, ...) represents a number N where N = (P1^a1)(P2^a2)...(Pn^an)... and Pi are the ordered primes.

Oh! And orthogonal vectors are relatively prime!

Comment author: ciphergoth 08 February 2010 11:15:17AM 1 point [-]

I'm not sure that the idea of orthogonality is defined for modules, is it? Is there a standard definition of an inner product for a Z-module?

Comment author: komponisto 08 February 2010 06:49:48PM 1 point [-]

I'm not sure that the idea of orthogonality is defined for modules, is it? Is there a standard definition of an inner product for a Z-module?

Yes; the same definition works. See here.

Comment author: Zack_M_Davis 09 February 2010 12:05:14AM 0 points [-]

Yay! I actually got something right!

Comment author: thomblake 28 January 2010 05:07:58PM 0 points [-]

What sub-field of mathematics is this?

Number theory, ne? Or is that too general?

Comment author: Blueberry 28 January 2010 05:57:34PM 2 points [-]

It looks like it's more abstract algebra (possibly applied to number theory) that byrnema is interested in. Check out Wikipedia on module.

Comment author: byrnema 28 January 2010 06:32:53PM 1 point [-]

Precisely! Thanks also.