Nested sequent calculus

In structural proof theory, the nested sequent calculus is a reformulation of the sequent calculus to allow deep inference.{{cite CiteSeerX |author1=Alwen Tiu |author2=Egor Ianovski |author3=Rajeev Goré |title=Grammar Logics in Nested Sequent Calculus: Proof Theory and Decision Procedures |pages=1 |citeseerx=10.1.1.1060.4978 }}