On the proof of Taylor's conjecture in multiply connected domains

In this Letter we extend the proof, by Faraco and Lindberg (2020), of Taylor's conjecture in multiply connected domains to cover arbitrary vector potentials and remove the need to impose restrictions on the magnetic field to ensure gauge invariance of the helicity integral. This extension allows us to treat general magnetic fields in closed domains that are important in laboratory plasmas and brings closure to a conjecture whose resolution has been open for almost 50 years.