The Aesthetics of ‘Speaking Objects’ in Aniki-Bóbó’s Anthropo-cosmo-morphic Material

The surface of the things which make up the pro-filmic constitutes the shell/ signifier chosen to shape the soul of the filmic world or its anthropo-cosmo-morphic image rendered by the techniques of film language. The result is the creation of a complex and multi-layered “possible world”, consisting of discursive parts that speak through the dramaturgy and aesthetics of the film, a socio-semantics which transfigures the matter of bodies and objects through the mechanisms of filmic re-signification. Amongst these, the intellectual montage as well as all the graphic and audio signs that appear on the scene can be identified. These signs stand out because of their metaphorical-discursive capacity, as will be analysed in the film Aniki-Bóbó (1942) by Manoel de Oliveira: the written words that serve to give voice to inanimate matter (Carlitos’ bag); the modelled forms which reproduce material allegories or doubles of the human body (the doll); the fragile materials that refer to the children’s fragility itself; the steel and iron of mechanised infrastructures showing the modernisation of the country; the classical architecture, the nature of the place and the free, open-air spaces of games, as opposed to closed spaces that recall underdeveloped pedagogical institutions; and among the latter, the liminal place par excellence, symbolised by the ‘Shop of Temptations’. In the filmic whole, bodies, places and objects are thus configured as interconnected parts of a single compact world, in which the cosmos is reflected in the anthropo, and the anthropo in the cosmos, in order to transfigure, in a metaphorical key, the immaterial culture referring to the changes in national identity. This allegorical fable of Portuguese pedagogical culture ultimately proposes the possibility of a social (and political) change, projected into a ‘just’ future without dictatorship (victory of good over evil).

From free algebras to proof bounds

(This is joint work with Nick Bezhanishvili).In the first part of our contribution, we review and compare existing constructions of finitely generated free algebras in modal logic focusing on step-by-step methods. We discuss the notions of step algebras and step frames arising from recent investigations, as well as the role played by finite duality.In the second part of the contribution, we exploit the potential of step frames for investigating proof-theoretic aspects. This includes developing a method which detects when a specific rule-based calculus Ax axiomatizing a given logic L has the so-called bounded proof property. This property is a kind of an analytic subformula property limiting the proof search space. We prove that every finite conservative step frame for Ax is a p-morphic image of a finite Kripke frame for L iff Ax has the bounded proof property and L has the finite model property. This result, combined with a `step version' of the classical correspondence theory turns out to be quite powerful in applications.

On Derivation Languages of a Class of Splicing Systems

Derivation languages are language theoretical tools that describe halting derivation processes of a generating device. We consider two types of derivation languages, namely Szilard and control languages for splicing systems where iterated splicing is done in non-uniform way defined by Mitrana, Petre and Rogojin in 2010. The families of Szilard (rules and labels are mapped in a one to one manner) and control (more than one rule can share the same label) languages generated by splicing systems of this type are then compared with the family of languages in the Chomsky hierarchy. We show that context-free languages can be generated as Szilard and control languages and any non-empty context-free language is a morphic image of the Szilard language of this type of system with finite set of rules and axioms. Moreover, we show that these systems with finite set of axioms and regular set of rules are capable of generating any recursively enumerable language as a control language.

Decision Algorithms for Fibonacci-Automatic Words, III: Enumeration and Abelian Properties

We continue our study of the class of Fibonacci-automatic words. These are infinite words whose nth term is defined in terms of a finite-state function of the Fibonacci representation of n. In this paper, we show how enumeration questions (such as counting the number of squares of length n in the Fibonacci word) can be decided purely mechanically, using a decision procedure. We reprove some known results, in a unified way, using our technique, and we prove some new results. We also examine abelian properties of these words. As a consequence of our results on abelian properties, we get the result that every nontrivial morphic image of the Fibonacci word is Fibonacci-automatic.

FACTORIZATIONS AND UNIVERSAL AUTOMATON OF OMEGA LANGUAGES

We extend the concept of factorization on finite words to ω-rational languages and show how to compute them. We define a normal form for Büchi automata and introduce a universal automaton for Büchi automata in normal form. We prove that, for every ω-rational language, this Büchi automaton, based on factorization, is canonical and that it is the smallest automaton that contains the morphic image of every equivalent Büchi automaton in normal form.

AVOIDING ABELIAN POWERS IN BINARY WORDS WITH BOUNDED ABELIAN COMPLEXITY

The notion of Abelian complexity of infinite words was recently used by the three last authors to investigate various Abelian properties of words. In particular, using van der Waerden's theorem, they proved that if a word avoids Abelian k-powers for some integer k, then its Abelian complexity is unbounded. This suggests the following question: How frequently do Abelian k-powers occur in a word having bounded Abelian complexity? In particular, does every uniformly recurrent word having bounded Abelian complexity begin in an Abelian k-power? While this is true for various classes of uniformly recurrent words, including for example the class of all Sturmian words, in this paper we show the existence of uniformly recurrent binary words, having bounded Abelian complexity, which admit an infinite number of suffixes which do not begin in an Abelian square. We also show that the shift orbit closure of any infinite binary overlap-free word contains a word which avoids Abelian cubes in the beginning. We also consider the effect of morphisms on Abelian complexity and show that the morphic image of a word having bounded Abelian complexity has bounded Abelian complexity. Finally, we give an open problem on avoidability of Abelian squares in infinite binary words and show that it is equivalent to a well-known open problem of Pirillo–Varricchio and Halbeisen–Hungerbühler.

Canonical formulas for K4. Part I: Basic results

This paper presents a new technique for handling modal logics with transitive frames, i.e. extensions of the modal system K4. In effect, the technique is based on the following fundamental result, to be obtained below in §3.Given a formula φ, we can effectively construct finite frames 1, …, n which completely characterize the set of all transitive general frames refuting φ. More exactly, an arbitrary general frame refutes φ iff contains a (not necessarily generated) subframe such that (1) i, for some i ϵ {1, …, n}, is a p-morphic image of (after Fine [1985] we say is subreducible to i), (2) is cofinal in , and (3) every point in that is not in does not get into “closed domains” which are uniquely determined in i, by φ.This purely technical result has, as it turns out, rather unexpected and profound consequences. For instance, it follows at once that if φ determines no closed domains in the frames 1, …, n associated with it, then the normal extension of K4 generated by φ has the finite model property and so is decidable. Moreover, every normal logic axiomatizable by any (even infinite) set of such formulas φ also has the finite model property. This observation would not possibly merit any special attention, were it not for the fact that the class of such logics contains almost all the standard systems within the field of K4 (at least all those mentioned by Segerberg [1971] or Bull and Segerberg [1984]), all logics containing S4.3, all subframe logics of Fine [1985], and a continuum of other logics as well.

The semidirect product of an inverse semigroup and a group

It is shown that a semidirect product of an inverse semigroup and a group, in that order, contains an inverse subsemigroup that is a retract and that, together with the retraction mapping, forms free inverse morphic image of the semidirect product. The congruence determined by the retraction mapping is shown to be determined by the semigroup of idempotents of the semidirect product.

Logics containing K4. Part II

This paper establishes another very general completeness result for the logics within the field of K4. With each finite transitive frame ℭ we may associate a formula — Bℭ which validates just those frames ℑ in which ℭ is not in a certain sense embeddable (to be exact, ℭ is not the p-morphic image of any subframe of ℑ. By a subframe logic we mean the result of adding such formulas as axioms to K4. The general result is that each subframe logic has the finite model property.There are a continuum of subframe logics and they include many of the standard ones, such as T, S4, S4.3, S5 and G. It turns out that the subframe logics are exactly those complete for a condition that is closed under subframes (any subframe of a frame satisfying the condition also satisfies the condition). As a consequence, every logic complete for a condition closed under subframes has the finite model property.It is ascertained which of the subframe logics are compact. It turns out that the compact logics are just those whose axioms express an elementary condition. Tests are given for determining whether a given axiom expresses an elementary condition and for determining what it is in case it does.In one respect the present general completeness result differs from most of the others in the literature. The others have usually either been what one might call logic based or formula based. They have usually either been to the effect that all of the logics containing a given logic are complete or to the effect that all logics whose axioms come from a given syntactically characterized class of formulas are complete. The present result is, by contrast, what one might call frame based. The axioms of the logics to be proved complete are characterized most directly in terms of their connection with certain frames.