SUPPES–STYLE SEQUENT CALCULUS FOR PROBABILITY · PDF fileSUPPES–STYLE SEQUENT...

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SUPPES–STYLE SEQUENT CALCULUS FOR PROBABILITY LOGIC Marija Boriˇ ci´ c Faculty of Organizational Sciences, University of Belgrade, Jove Ili´ ca 154, 11000 Belgrade, Serbia e–mail: [email protected] Abstract. Deduction relation naturally connecting a set Γ of hypotheses with a conclusion A, usually denoted by Γ A, presents a basic notion of traditional logic. The framework of approximative and vague reasoning needs a new concept of such a connection enabling to express that ’A follows from Γ with probability p’. In this paper, following the Gentzen’s approach to the formalization of the deduction relation, we introduce a system LKprob(ε) making it possible to work with the expressions of the form Γ n Δ, a generalization of Gentzen’s sequents Γ Δ enriched by the Suppes–style formulae, meaning that ’the truthfulness probability of the sequent Γ Δ is greater than or equal to 1 - ’, for a given small real ε> 0 and any natural number n. We prove that our system is sound and complete with respect to the Carnap–Popper–type probability models. The results contained in this paper were partially presented at the European Summer Meetings of Association for Symbolic Logic, Logic Colloquium 2012, held in Manchester on July 12–18, 2012 (Bulletin of Symbolic Logic, Vol. 20, No. 3, 2015, pp. 401–402 (Abstract)), and Logic Colloquium 2014, held in Vienna on July 14–19, 2014 (Bulletin of Symbolic Logic, Vol. 21, No. 1, 2014, p. 60 (Abstract)). AMS 2010 Mathematics Subject Classification: 03B48, 03B50, 03B05, 03B55. Key words: consistency; probability; soundness; completeness.

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SUPPES–STYLE SEQUENT CALCULUS FOR PROBABILITY LOGIC

Marija BoricicFaculty of Organizational Sciences, University of Belgrade,

Jove Ilica 154, 11000 Belgrade, Serbiae–mail: [email protected]

Abstract. Deduction relation naturally connecting a set Γ of hypotheses with aconclusion A, usually denoted by Γ ` A, presents a basic notion of traditional logic. Theframework of approximative and vague reasoning needs a new concept of such a connectionenabling to express that ’A follows from Γ with probability p’. In this paper, followingthe Gentzen’s approach to the formalization of the deduction relation, we introduce asystem LKprob(ε) making it possible to work with the expressions of the form Γ `n ∆, ageneralization of Gentzen’s sequents Γ ` ∆ enriched by the Suppes–style formulae, meaningthat ’the truthfulness probability of the sequent Γ ` ∆ is greater than or equal to 1− nε’,for a given small real ε > 0 and any natural number n. We prove that our system is soundand complete with respect to the Carnap–Popper–type probability models.

The results contained in this paper were partially presented at the European SummerMeetings of Association for Symbolic Logic, Logic Colloquium 2012, held in Manchesteron July 12–18, 2012 (Bulletin of Symbolic Logic, Vol. 20, No. 3, 2015, pp. 401–402(Abstract)), and Logic Colloquium 2014, held in Vienna on July 14–19, 2014 (Bulletinof Symbolic Logic, Vol. 21, No. 1, 2014, p. 60 (Abstract)).

AMS 2010 Mathematics Subject Classification: 03B48, 03B50, 03B05, 03B55.Key words: consistency; probability; soundness; completeness.