Objective 1. Philosophical Foundations. Progress on radical substructural logics ST and TS by the study of their characterization in terms of natural set theoretic operations and by the study of lattices formed by many-valued logics. We also made progress on the conceptualization of substructurality and the availability of formal methods to show how classical reasoning can be retained in a substructural setting (classical recapture). In connection to this objective, we also extended the analysis of radical substructurality to alternative contexts (intuitionistic logic, weak Kleene logics, four-valued semantics, probabilistic consequence relations).
The work-package related to this objective involves a significant number of researchers (9 ER and 4 ESR) and secondments (39 months of secondments planned). The implementation of these was fruitful in collaborations between experienced and early stage researchers. All the scientific events up to date (inaugural conference, workshop, intensive courses, summer school) relate to this scientific objective. In addition to these, we organized 10 extra events of networking and knowledge sharing that were not planned in the original proposal.
Objective 2. Logic. In relation to this objective, we advanced knowledge of the technical aspects of radical substructural logics, focusing primarily on the development of different sort of calculus (sequents, labelled sequents, natural deduction) and model theoretic and algebraic approximations to radical substructural logics. We also conducted research on the applications of substructural logics to different domains like: self-applicable truth, conditionals and epistemic phenomena.
The work-package related to objective 2 is the largest with 50 months of secondments (+14 months in KCL) and 23 researchers (9 ESR and 14 ER). The secondments, from EU institutions to either CUNY or CONICET were extremely fruitful and lead to collaborations between experienced researchers and younger scholars in the form of paper writing and, also, some co-supervisions. All of PLEXUS’ scientific events had an impact on WP2 and, as we mentioned in relation to objective 1, during this period more scientific events were implemented within the PLEXUS network than originally planned.
Objective 3. The Metainferences Inventory & Metainferences Prover. The progress of the work-package related to objective 3 concerns (i) the conceptualization, design, debriefing and pretesting of the Inventory and (ii) the analysis of theorem provers and the first steps towards the construction of a theorem prover for metainferences. Regarding (i) the team in Navarra prepared a first draft of the Inventory with two pilot tests. Regarding (ii) the team in CONICET advanced on the accommodation of the Python package Logics to trees for metainferences for Strong Kleene Logics as well as with the adaptation of the web interface Taut. Two PhD students in Navarra were trained and took the first steps towards the construction of a tree proof generator for metainferences for Strong Kleene Logics.
There were five secondments in this period in the work-package for objective 3 involving two ESRs and two ERs. One of the Intensive Courses was dedicated to knowledge sharing of experimental methods (Behavioural Logic & Principles of Assessing Behaviour). The Workshop on Logic and Reasoning held in Buenos Aires in November 2024 was dedicated to this WP. One of the courses of the Summer School explained the fundamentals of automated reasoning in ProLog.