This package provides commands to typeset proof trees in the style of sequent calculus and related systems.

The commands allow for writing inferences with any number of premises and alignment of successive formulas on an arbitrary point. Various options allow complete control over spacing, styles of inference rules, placement of labels, etc.

The package requires pgfkeys (from the PGF/TikZ bundle) for the option system.

See also bussproofs.

The author is Emmanuel Beffara. The package is Copyright © 2015 Emmanuel Beffara.