Unguarded Recursion on Coinductive Resumptions

• Main Authors: Goncharov, Sergey, Schröder, Lutz, Rauch, Christoph, Jakob, Julian
• Format: Journal Article
• Language: English
• Published: 24-08-2018
• Subjects: Computer Science - Logic in Computer Science
• DOI: 10.48550/arxiv.1405.0854

Logical Methods in Computer Science, Volume 14, Issue 3 (August
27, 2018) lmcs:4773 We study a model of side-effecting processes obtained by starting from a
monad modelling base effects and adjoining free operations using a cofree
coalgebra construction; one thus arrives at what one may think of as types of
non-wellfounded side-effecting trees, generalizing the infinite resumption
monad. Correspondingly, the arising monad transformer has been termed the
coinductive generalized resumption transformer. Monads of this kind have
received some attention in the recent literature; in particular, it has been
shown that they admit guarded iteration. Here, we show that they also admit
unguarded iteration, i.e. form complete Elgot monads, provided that the
underlying base effect supports unguarded iteration. Moreover, we provide a
universal characterization of the coinductive resumption monad transformer in
terms of coproducts of complete Elgot monads.