In:
https://github.com/metamath/set.mm/issues/2648
@savask reveals some great analysis of theorems that don't use some of their 
hypotheses.
In most cases this is something that should be fixed.
It's great work, thanks!!

However, as @savask notes:
> ... there are also theorems which contain useless hypotheses by design, like 
> a1ii, which shouldn't be corrected.

I think every assertion that intentionally does *not* use all its hypotheses 
should be *clearly* documented
in its descriptive comment. I think we should have a convention so we can 
automatically detect
those cases later, similar to "(New usage is discouraged.)". That way, both 
humans and automated
analysis programs will know that this is on purpose.

I propose using these comment markings for assertions ($a and $p) where 
hypotheses
are not used on *purpose*:
* "(Intentionally unused hypothesis)" if exactly one hypothesis is unused
* "(Intentionally unused hypotheses)" if more than one hypotheses are unused

I was originally going to propose both simply because that's how English 
plurals work.
However, there's an error-detect advantage to making their meaning different -
if you only intended 1 hypothesis to be unused, but more than one is, it
can still be caught.

--- David A. Wheeler

-- 
You received this message because you are subscribed to the Google Groups 
"Metamath" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
To view this discussion on the web visit 
https://groups.google.com/d/msgid/metamath/C93E2B1C-03A7-420B-AD4D-CD1E9C843B66%40dwheeler.com.

Reply via email to