On Friday, June 14, 2019 at 4:06:03 PM UTC+2, Alexander van der Vekens 
wrote:
>
> Why is the theorem ~ 4syl discouraged? The comment says:
>
> The use of this theorem is marked "discouraged" because it can cause the 
>> "minimize" command to have very long run times.  However, feel free to use 
>> "minimize 4syl /override" if you wish.  Remember to update the Travis 
>> "discouraged" file if it gets used.
>>
>
> Actually, there are 191 uses of "4syl" in set.mm!  So is there (still) a 
> relevant impact on "minimize" or another reason why it is discouraged?
>

The reason is still the same: launch a "> minimize 4syl" on a long proof, 
and it will take a very long time.  As Norm told me when I proposed to add 
4syl, the "minimize" algorithm has something like exponential time 
complexity in the number of $e-hypotheses of the theorem to minimize with, 
and 4syl has four $e-hypotheses...

I agree that it is a useful theorem, but you can see manually if it is 
worth to launch a "minimize 4syl/override": if your proof already uses 3syl 
and chains it with a syl, for instance.

Benoit

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