On Monday, November 4, 2013 1:29:10 AM UTC-8, Georgi Guninski wrote:
>
> On Sun, Nov 03, 2013 at 09:51:15AM -0800, Nils Bruin wrote: 
> > On Sunday, November 3, 2013 6:36:35 AM UTC-8, John Cremona wrote: 
> > > 
> > > The function is called global_height(): 
> > > 
> > > sage: K.<a> = NumberField(x^3-2) 
> > > sage: b = a+1 
> > > sage: b.global_height() 
> > > 0.366204096222703 
> > > 
> > > John Cremona 
> > > 
> >   
> > That doesn't quite do the trick, though. For ABC, you'd need the height 
> of 
> > the triple (a:b:c), not of the individual points. I think there are some 
> > tickets about heights for arithmetic dynamics? I'd think they would need 
> > naive height on projective space somewhere as well. 
> > 
> > It should be pretty straightforward to write something yourself: 
> >  - clear denominators on your triple (a,b,c) [not necessarily minimally 
> - 
> > if your ring of integers isn't a PID you might not be able to] 
> >  - compute the archimedean contribution by taking max abs of the complex 
> > (and real) embeddings (take complex places twice) 
> >  - divide by Norm (ideal generated by integral representatives) 
> > 
>
>
> Thank you for the replies. 
>
> Isn't it possible to define the quality only in 
> terms of the norm and the integer radical, 
> something like this: 
>
> q(a,b,c) = max( norm(a),norm(b),norm(c) ) / 
>            (log(Delta(K)) + degree(K) * log(radical(norm(a*b*c))) ) 
>
> with the restriction the norms of a,b,c to be coprime ? 
>
> Probably this needs some patching. 
>
> Is the ABC for this type of quality known and 
> does it make sense at all ? 
>
>

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