mathlib

c5045853 - fix(number_theory/number_field): make ring_of_integers_algebra not an instance (#12331)

fix(number_theory/number_field): make ring_of_integers_algebra not an instance (#12331) This issue has caused problems for at least two of Kevin's PhD students; it is better to remove it for now or disable it temporarily. c.f. https://leanprover.zulipchat.com/#narrow/stream/113488-general/topic/diamond.20for.20monoid.20instance.20on.20ideals Co-authored-by: Eric Rodriguez <37984851+ericrbg@users.noreply.github.com>