1 Introduction
2 Lie Modules
3 Nilpotency
3.1 Ideal Operations and Nilpotent Lie Modules
3.2 Acting Nilpotently
4 Engel’s Theorem
4.1 Engelian Lie Algebras
by exactI
\(\forall \) pattern’ as well as the explicit mention of typeclasses that could be inferred (like add_comm_group
, module
etc). One would prefer to write simply \(\forall \) (M:
u
\({_{4}}\)), [[lie_module R L M]]
rather than the three lines appearing above. This situation is likely to improve after Mathlib is migrated to Lean 4.4.2 Passing to the Image in End(M)
(to_endomorphism R L M).range
, i.e. \(L'\), is a Lie algebra and that M is naturally a Lie module over \(L'\). All of this is achieved by typeclass instances registered far away, with no direct connection to Engel’s theorem.lie_subalgebra R A
. See also [6] section 5.) The proof follows from the binomial theorem. Taking \(A = {{\,\textrm{End}\,}}(M)\) the lemma states that \(L'\) acts nilpotently on itself.
4.3 The Main Argument
-
\(K'\) is a Lie subalgebra of \(L'\),
-
\(K'\) strictly contains K,
-
K is an ideal in \(K'\).
5 The Zero Root Space
root_space H (0: H
\(\rightarrow \) R)
[src]; informally it is:6 Conclusion
Acknowledgements
master
branch of the open-source Mathlib
repository, with links appearing throughout the text.