[net.math] not Groups

colonel@ellie.UUCP (Col. G. L. Sicherman) (03/12/86)

> You might be interested in loops, where the multiplication has 
> different left and right inverses. Unfortunately, elementary
> accounts are rare. There is a volume in the Springer Ergebnisse
> series on loops, written by Bruck. They're useful for representing
> Latin Squares. There's a more recent reference which currently
> escapes me.

The last book I read on Latin Squares called them "quasigroups" or
something like that. "Loops" sounds much better--if they're indeed
the same.

	"An antiset is a mathematical object that fails to
	 contain each of its members." --E. P. B. Umbugio
-- 
Col. G. L. Sicherman
UU: ...{rocksvax|decvax}!sunybcs!colonel
CS: colonel@buffalo-cs
BI: csdsicher@sunyabva

kwh@bentley.UUCP (KW Heuer) (03/16/86)

In article <886@ellie.UUCP> ellie!colonel (Col. G. L. Sicherman) writes:
>The last book I read on Latin Squares called them "quasigroups" or
>something like that. "Loops" sounds much better--if they're indeed
>the same.

If I remember correctly, a loop is a quasigroup with an identity element.
The quasigroup axioms include cancellation (if xz=yz or zx=zy then x=y)
but not associativity; an associative quasigroup (or loop) is a group.
Another way to say this is that an object which is both a quasigroup and
a semigroup is a group.

What's the origin of the name "Loop"?  Is it a contraction of "Latin-
square group", or what?  (I see nothing that suggests roundness in either
loops or rings.)

ladkin@kestrel.ARPA (Peter Ladkin) (03/18/86)

In article <886@ellie.UUCP>, colonel@ellie.UUCP (Col. G. L. Sicherman) writes:
> 
> The last book I read on Latin Squares called them "quasigroups" or
> something like that. "Loops" sounds much better--if they're indeed
> the same.

Whoops! I guess I don't have my definitions right. They're very
close, but not the same. I think one has an identity and one not.

Peter Ladkin