Unifying Guarded and Unguarded Iteration

@inproceedings{Goncharov2017UnifyingGA,
  title={Unifying Guarded and Unguarded Iteration},
  author={Sergey Goncharov and Lutz Schr{\"o}der and Christoph Rauch and Maciej Pir{\'o}g},
  booktitle={FoSSaCS},
  year={2017}
}
Models of iterated computation, such as completely iterative monads, often depend on a notion of guardedness, which guarantees unique solvability of recursive equations and requires roughly that recursive calls happen only under certain guarding operations. On the other hand, many models of iteration do admit unguarded iteration. Solutions are then no longer unique, and in general not even determined as least or greatest fixpoints, being instead governed by quasi-equational axioms. Monads that… 

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