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 author       = {Carlos Caleiro and Jaime Ramos},
 year         = {2007},
 title        = {Combining classical and intuitionistic implications},
 booktitle    = {Proceedings of 6th International Symposium on Frontiers of Combining Systems (FroCoS)},
 organization = {Springer},
 pages        = {118--132},
 doi          = {10.1007/978-3-540-74621-8_8},
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 author       = {Carlos Caleiro and Jaime Ramos},
 year         = {2007},
 title        = {From fibring to cryptofibring. A solution to the collapsing problem},
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 volume       = {1},
 number       = {1},
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 author       = {Fari{\~n}as del Cerro, Luis and Andreas Herzig},
 year         = {1996},
 title        = {Combining classical and intuitionistic logic},
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 booktitle    = {Proceedings of the International Workshop on Frontiers of Combining Systems (FroCoS)},
 publisher    = {Kluwer Academic Publishers},
 pages        = {93--102},
 doi          = {10.1007/978-94-009-0349-4_4},
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 author       = {Michael De},
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 title        = {{Empirical negation}},
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 author       = {Michael De and Hitoshi Omori},
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 title        = {More on empirical negation},
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 booktitle    = {Advances in Modal Logic},
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 publisher    = {College Publications},
 pages        = {114--133},
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 author       = {Michael De and Hitoshi Omori},
 year         = {2016},
 title        = {Classical and Empirical Negation in Subintuitionistic Logic.},
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 booktitle    = {Advances in Modal Logic},
 volume       = {11},
 publisher    = {College Publications},
 pages        = {217--235},
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 title        = {An overview of fibred semantics and the combination of logics},
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 booktitle    = {Proceedings of the International Workshop on Frontiers of Combining Systems (FroCoS)},
 publisher    = {Kluwer Academic Publishers},
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 doi          = {10.1007/978-94-009-0349-4_1},
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 title        = {{A paraconsistent extension of {S}ylvan's logic}},
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 title        = {Extensions of intuitionistic logic without the deduction theorem: some simple examples},
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@book(Humberstone2011connectives,
 author       = {Lloyd Humberstone},
 year         = {2011},
 title        = {The connectives},
 publisher    = {MIT Press},
 doi          = {10.7551/mitpress/9055.001.0001},
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 author       = {Ingebrigt Johansson},
 year         = {1937},
 title        = {Der Minimalkalk\"ul, ein reduzierter intuitionistischer Formalismus},
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@article(Kurokawa2009hypersequent,
 author       = {Hidenori Kurokawa},
 year         = {2009},
 title        = {Hypersequent calculi for intuitionistic logic with classical atoms},
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 volume       = {161},
 number       = {3},
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@article(Lewitzka2017,
 author       = {Steffen Lewitzka},
 year         = {2017},
 title        = {A modal logic amalgam of classical and intuitionistic propositional logic},
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 number       = {1},
 pages        = {201--212},
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 author       = {Paqui Lucio},
 year         = {2000},
 title        = {Structured sequent calculi for combining intuitionistic and classical first-order logic},
 booktitle    = {Proceedings of the 3rd International Workshop on Frontiers of Combining Systems (FroCoS)},
 organization = {Springer},
 pages        = {88--104},
 doi          = {10.1007/10720084\_7},
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@article(NikiBSL2020I,
 author       = {Satoru Niki},
 year         = {2020},
 title        = {{Empirical negation, co-negation and contraposition Rule I: {S}emantical investigations}},
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 volume       = {49},
 number       = {3},
 pages        = {231--253},
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@article(NikiBSL2020II,
 author       = {Satoru Niki},
 year         = {2020},
 title        = {{Empirical negation, co-negation and contraposition Rule II: {P}roof-theoretical investigations}},
 journal      = {Bulletin of the Section of Logic},
 volume       = {49},
 number       = {4},
 pages        = {359\IeC{\textendash}375},
 doi          = {10.18778/0138-0680.2020.13},
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@incollection(NikiOmoriAiMLsubmitted,
 author       = {Satoru Niki and Hitoshi Omori},
 year         = {2020},
 title        = {Actuality in intuitionistic logic},
 editor       = {Nicola Olivetti and Rineke Verbrugge and Sara Negri and Gabriel Sandu},
 booktitle    = {Advances in Modal Logic},
 volume       = {13},
 publisher    = {College Publications},
 pages        = {459--479},
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@article(NikiOmoriOmega,
 author       = {Satoru Niki and Hitoshi Omori},
 year         = {2021},
 title        = {{A note on Humberstone's constant $\Omega$}},
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 volume       = {56},
 pages        = {75--99},
 doi          = {10.4467/20842589RM.21.004.14376},
)
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 number       = {3},
 pages        = {687--722},
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@article(pereira2017normalization,
 author       = {Luiz Carlos Pereira and Ricardo Oscar Rodriguez},
 year         = {2017},
 title        = {Normalization, soundness and completeness for the propositional fragment of Prawitz\IeC{\textquoteright}ecumenical system},
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 volume       = {73},
 number       = {3/4},
 pages        = {1153--1168},
 doi          = {10.17990/RPF/2017_73_3_1153},
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@inproceedings(pimentel2018,
 author       = {Elaine Pimentel and Luiz Carlos Pereira and Valeria de Paiva},
 year         = {2018},
 title        = {A proof theoretical view of ecumenical systems},
 booktitle    = {Proceedings of the 13th Workshop on Logical and Semantic Frameworks with Applications},
 pages        = {109--114},
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@article(pimentel2019ecumenical,
 author       = {Elaine Pimentel and Luiz Carlos Pereira and Valeria de Paiva},
 year         = {2021},
 title        = {An ecumenical notion of entailment},
 journal      = {Synthese},
 volume       = {198},
 pages        = {5391--5413},
 doi          = {10.1007/s11229-019-02226-5},
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@incollection(Prawitz2015,
 author       = {Dag Prawitz},
 year         = {2015},
 title        = {Classical versus intuitionistic logic},
 editor       = {Edward Hermann Haeusler and Wagner de Campos Sanz and Bruno Lopes},
 booktitle    = {Why is this a Proof?: Festschrift for Luiz Carlos Pereira},
 publisher    = {College Publications},
 pages        = {15--32},
)
@article(PriestdaCL,
 author       = {Graham Priest},
 year         = {2009},
 title        = {{Dualising intuitionistic negation}},
 journal      = {Principia},
 volume       = {13},
 number       = {2},
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 doi          = {10.5007/1808-1711.2009v13n2p165},
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 year         = {1994},
 title        = {{Subintuitionistic Logics}},
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@book(schwichtenberg2011proofs,
 author       = {Helmut Schwichtenberg and Stanley S Wainer},
 year         = {2011},
 title        = {Proofs and computations},
 publisher    = {Cambridge University Press},
 doi          = {10.1017/CBO9781139031905},
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@article(segerberg1968propositional,
 author       = {Krister Segerberg},
 year         = {1968},
 title        = {Propositional logics related to {H}eyting's and {J}ohansson's},
 journal      = {Theoria},
 volume       = {34},
 number       = {1},
 pages        = {26--61},
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@inproceedings(toyooka2021analytic,
 author       = {Masanobu Toyooka and Katsuhiko Sano},
 year         = {2021},
 title        = {Analytic Multi-Succedent Sequent Calculus for Combining Intuitionistic and Classical Propositional Logic},
 editor       = {Sujata Ghosh and R. Ramanujam},
 booktitle    = {ICLA 2021 Proceedings},
 pages        = {128--133},
 url          = {https: //www.isichennai.res.in/~sujata/icla2021/proceedings.pdf.},
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@book(TroelstravanDalen1988,
 author       = {Anne Sjerp Troelstra and Dirk van Dalen},
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@book(TroelstraSchwichtenberg2000,
 author       = {Anne Sjerp Troelstra and Helmut Schwichtenberg},
 year         = {2000},
 title        = {Basic proof theory},
 publisher    = {Cambridge University Press},
 doi          = {10.1017/CBO9781139168717},
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