From: "Ronnie Brown" <ronnie.profbrown@btinternet.com>
To: "\"Categories list\"" <categories@mta.ca>
Subject: Re: Homomorphisms on Z^n
Date: Sat, 15 Sep 2007 10:02:50 +0100 [thread overview]
Message-ID: <E1IWcXd-0007SB-Tq@mailserv.mta.ca> (raw)
Michael,
I think Christopher Zeemann did something on this in or around the 1950s
but cannot at the moment access mathscinet to check.
In the 1970s several of us extended Pontrjagin duality:
15. (with P.J. HIGGINS and S.A. MORRIS), ``Countable products of
lines and circles: their closed subgroups, quotients and duality
properties'', {\em Math. Proc. Camb. Phil. Soc.} 78 (1975) 19-32.
in particular defining `strong duality'.
Ronnie
----- Original Message -----
From: "Michael Barr" <barr@math.mcgill.ca>
To: "Categories list" <categories@mta.ca>
Sent: Friday, September 14, 2007 1:34 PM
Subject: categories: Homomorphisms on Z^n
> Many years ago (at least 45) Harrison mentioned to me that for any n
> (including infinite cardinals), Hom(Z^n,Z) = n.Z, in other words the
> Z-dual of the product is the sum. This is obviously a very special
> property of Z, almost the negation of injectivity. Has anyone on this
> list ever seen this before and can give me a reference?
>
> Michael
>
>
>
>
>
> --
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next reply other threads:[~2007-09-15 9:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-15 9:02 Ronnie Brown [this message]
-- strict thread matches above, loose matches on Subject: below --
2007-09-18 16:53 Stephen Urban Chase
2007-09-14 12:34 Michael Barr
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