A bstract We construct off-shell recursion relations for arbitrary loop-level scattering amplitudes beyond the conventional tree-level ϕ 4 -theory and Yang-Mills theory. define a quantum perturbiner expansion that includes loop corrections from effective action formalism by identifying external source. Our method clearly shows how becomes an current generating function. Instead of using classic...

In a previous paper we introduced a system of recursion operators for formulating pure logic programs, dispensing with explicit recursions. The recursion operators, some of which are similar to higher-order functions known from functional programming, take the form of quasi-higher order predicates. In this paper we identify a comprehensive class of logic programs called primitive recursive rela...

One of the most satisfactory results in process theory is Milner’s axiomatization of strong bisimulation for regular CCS. This result holds for open terms with finite-state recursion. Wang has shown that timed bisimulation can also be axiomatized, but only for closed terms without recursion. In this paper, we provide an axiomatization for timed bisimulation of open terms with finite-state recur...

This paper presents structural recursion as the basis of the syntax and semantics of query languages for semistructured data and XML. We describe a simple and powerful query language based on pattern matching and show that it can be expressed using structural recursion, which is introduced as a top-down, recursive function, similar to the way XSL is deened on XML trees. On cyclic data, structur...

In this paper we describe the extraction of “efficient” recursion schemes from proofs of well-founded induction principles. This is part of a larger methodology; when these well-founded induction principles are used in proofs, the structure of the program extracted from the proof is determined by the recursion scheme inhabiting the induction principle. Our development is based on Paulson’s pape...