intuitionistic logic ~ programming
natural deduction ~ lambda-calculus
Hilbert system ~ combinatory logic {S, K}
Gentzen system=sequent calculus ~ ?
What would you write in place of the question mark?
Update 0: Common mathematical tree notation for proofs is too cumbersome and redundant. I need a language as compact as e.g.:
data Proof = Apply Proof Proof | S | K {- Haskell, combinatory logic -}
Update 1: After following the links suggested by commentators I found this perfectly concrete and accessible article: "Hugo Herbelin. A Lambda-calculus Structure Isomorphic to Gentzen-style Sequent Calculus Structure." There, "?" language is named "the usual interpretation of LJ cut-free proofs by normal lambda-terms", i.e. is a subset made out of lambda-calculus.

