I'm studying QM out of Sakurai's book and on page 95 (equation 2.3.47), he states the Baker-Hausdorff Lemma without proof. I've scoured the internet in search of an elementary proof (i.e. one that does not rely on lie algebras, etc.), but have come up empty. I was wondering if anyone knew of a place I could find a proof online.(adsbygoogle = window.adsbygoogle || []).push({});

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Baker-Hausdorff Lemma

**Physics Forums | Science Articles, Homework Help, Discussion**