A new graphical calculus of proofs
  We offer a simple graphical representation for proofs of intuitionistic logic, which is inspired by proof nets and interaction nets (two formalisms originating in linear logic). This graphical calculus of proofs inherits good features from each, but is not constrained by them. By the Curry-Howard isomorphism, the representation applies equally to the lambda calculus, offering an alternative diagrammatic representation of functional computations. 
Sandra Alves (University of Porto), Maribel Fern\'andez (King's   College London), Ian Mackie (Ecole Polytechnique)
cs.LO