A multi-focused proof system isomorphic to expansion proofs

@article{Chaudhuri2016AMP,
  title={A multi-focused proof system isomorphic to expansion proofs},
  author={Kaustuv Chaudhuri and Stefan Hetzl and Dale Miller},
  journal={J. Log. Comput.},
  year={2016},
  volume={26},
  pages={577-603}
}
The sequent calculus is often criticized for requiring proofs to contain large amounts of low-level syntactic details that can obscure the essence of a given proof. Because each inference rule introduces only a single connective, sequent proofs can separate closely related steps---such as instantiating a block of quantifiers---by irrelevant noise. Moreover, the sequential nature of sequent proofs forces proof steps that are syntactically non-interfering and permutable to nevertheless be written… 

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