The purpose of this paper is to argue that the hybrid formalism fits naturally in the context of David Lewis’s counterfactual logic and that its introduction into this framework is desirable. This hybridization enables us to regard the inference “The pig is Mary; Mary is pregnant; therefore the pig is pregnant” as a process of updating local information (which depends on the given situation) by using global information (independent of the situation). Our hybridization also has the following technical advantages: (i) (...) it preserves the completeness and decidability of Lewis’s logic; (ii) it allows us to characterize the Limit Assumption as a proof-rule with some side-conditions; and (iii) it enables us to establish a general Kripke completeness result by using the proof-rule corresponding to the Limit Assumption. Keywords Counterfactual logic - David Lewis - Contextually definite description - Hybrid logic - Arthur Prior - The limit assumption - Strong completeness - Decidability - Bisimulation - Pure completeness. (shrink)

Standard notions of democracy assume people’s equality. This poses a dilemma for conceptualising democracy in the context of caregiving and receiving among asymmetrically positioned people. One way to overcome this dilemma is to generalise dependency as a universal human condition. However, addressing how democracy is possible among unequally situated people is necessary for developing a distinctive theory of democracy that takes the fact of human dependency seriously. To this end, I develop an expanded conception of democracy that goes beyond the (...) individual exercise of voice to that of interacting with others according to an ethic of care that supports the autonomy of others. Drawing on Hannah Arendt’s notion of a ‘common world’ as a web of narratives arising from the complex interaction of plural perspectives, I argue that democracy conceived as ‘being part of the story’ can foster such an ethic. This has practical relevance for societies where the sites of social cooperation are shifting from employment to care. (shrink)

The logic of the hide and seek game $$\textbf{LHS}$$ was proposed to capture interactions between agents in pursuit-evasion environments. In this paper, we explore a hybrid extension of $$\textbf{LHS}$$ and show that such an extension is beneficial in several aspects. We will show that it improves the technical properties of the resulting logical system, and expands the potential applications of the system. Specifically, we will investigate the expressive power of the hybrid logic of the hide and seek game $${\mathcal {H}}(\textbf{LHS})$$ (...) and its crucial fragment $${\mathcal {H}}(\textbf{LHS}^{-})$$, at both model and frame levels. We will present complete Hilbert-style proof systems for both the logics $${\mathcal {H}}(\textbf{LHS}^{-})$$ and $${\mathcal {H}}(\textbf{LHS})$$, which in fact provides a solution to a known open problem. (shrink)

Cells utilize diverse organelles to maintain homeostasis and to respond to extracellular stimuli. Recently, multifaceted aspects of organelle stress caused by various factors have been emerging. The endosome is an essential organelle, functioning as the central hub for membrane trafficking in cooperation with the ubiquitin system. However, knowledge regarding endosomal stress, which refers to organelle stress of the endosome, is currently limited. We recently revealed ubiquitin‐mediated endosomal stress of early endosomes (EEs) and its responsive signaling pathways. These findings shed light (...) on the relevance of ubiquitin‐mediated endosomal stress to physiological and pathological processes. Here, we present a hypothesis that ubiquitin‐mediated endosomal stress may have significant roles in biological contexts and that ubiquitin‐specific protease 8 is a key regulator of ubiquitin clearance from EEs. (shrink)

Genome maintenance requires various nucleoid-associated factors in prokaryotes. Among them, the SMC protein has been thought to play a static role in the organization and segregation of the chromosome during cell division. However, recent studies have shown that the bacterial SMC is required to align left and right arms of the emerging chromosome and that the protein dynamically travels from origin to Ter region. A rod form of the SMC complex mediates DNA bridging and has been recognized as a machinery (...) responsible for DNA loop extrusion, like eukaryotic condensin or cohesin complexes, which act as chromosome organizers. Attention is now turning to how the prototype of the complex is loaded on the entry site and translocated on chromosomal DNA, explaining its overall conformational changes at atomic levels. Here, we review and highlight recent findings concerning the prokaryotic SMC complex and discuss possible mechanisms from the viewpoint of protein architecture. Recent studies show dynamic movements of the prokaryotic SMC protein complex: initial loading, translocation on DNA for bacterial chromosome organization. The recent structural models of the protein also provide a new vision for the structure-function relationship. (shrink)

This paper deals with two main topics: One is a semantical investigation for a bimodal language with a modal operator \blacksquare associated with the intersection of the accessibility relation R and the inequality ≠. The other is a generalization of some of the former results to general extended languages with modal operators. First, for our language L\sb{\square\blacksquare}, we prove that Segerberg's theorem (equivalence between finite frame property and finite model property) fails and establish both van Benthem-style and Goldblatt-Thomason-style characterizations. We (...) extract the notion of \blacksquare-realizer (a generalization of bulldozing) as an essence from the proofs of our results. Second, we generalize the notion of \blacksquare-realizer and prove quite general versions of these semantical characterization results. The known and previously unknown characterization results for almost all of the languages extended with modal operators already proposed will be immediate corollaries. (shrink)

正しいから証明できるのか、証明できるから正しいのか。数学にとって証明とは何か、正しさとは何なのかは数学基礎論の根本的な問題である。様相論理を軸とした、証明と真理に関わる数学基礎論の古典的な結果から最先 端の議論までを解説した。.

This article discusses three policy ideas that address the limitations of the traditional welfare state: universal basic income (UBI), universal basic services (UBS), and the social economy. As a lens from which to evaluate these policy alternatives, we develop a concept of active citizenship as an interactive and recursive process between people’s equal political influence and the institutional conditions in which they are placed. While the social policy discourse on active citizenship has centred on the debate between increasing individual responsibilities (...) or enhancing people’s capabilities, our conception recentres the political dimension of active citizenship as people’s capacity, not only to exercise individual self-determination, but also collective self-determination over shared conditions. We conclude that, in addition to the conditions for security and autonomy, opportunities for organised social cooperation are necessary to achieve a virtuous cycle between people’s political influence and the institutions that support it. (shrink)