,
Adam Donadille
Creative Commons Attribution 4.0 International license
We are interested in proving input-output properties of functions that handle infinite data such as streams or non-wellfounded trees. We provide a finitary refinement type system which is (sound and) complete for Scott-open properties defined in a fixpoint-like logic. Working on top of Abramsky’s Domain Theory in Logical Form, we build from the well-known fact that the Scott domains interpreting recursive types are spectral spaces. The usual symmetry between Scott-open and compact-saturated sets is reflected in logical polarities: positive formulae allow for least fixpoints and define Scott-open sets, while negative formulae allow for greatest fixpoints and define compact-saturated sets. A realizability implication with the expected (contra)variance on polarities allows for non-trivial input-output properties to be formulated as positive formulae on function types.
@InProceedings{riba_et_al:LIPIcs.FSCD.2026.28,
author = {Riba, Colin and Donadille, Adam},
title = {{A Complete Finitary Refinement Type System for Scott-Open Properties}},
booktitle = {11th International Conference on Formal Structures for Computation and Deduction (FSCD 2026)},
pages = {28:1--28:18},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-433-8},
ISSN = {1868-8969},
year = {2026},
volume = {378},
editor = {Pfenning, Frank},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2026.28},
URN = {urn:nbn:de:0030-drops-263780},
doi = {10.4230/LIPIcs.FSCD.2026.28},
annote = {Keywords: Domain Theory, Temporal Logic, Refinement Types}
}