This study aims to examine key attributes affecting Airbnb users' satisfaction and dissatisfaction through the analysis of online reviews. A corpus that comprises 59,766 Airbnb reviews form 27,980 listings located in 12 different cities is analyzed by using both Latent Dirichlet Allocation and supervised LDA approach. Unlike previous LDA based Airbnb studies, this study examines positive and negative Airbnb reviews separately, and results reveal the heterogeneity of satisfaction and dissatisfaction attributes in Airbnb accommodation. In particular, the emergence of the topic (...) “guest conflicts” in this study leads to a new direction in future sharing economy accommodation research, which is to study the interactions of different guests in a highly shared environment. The results of topic distribution analysis show that in different types of Airbnb properties, Airbnb users attach different importance to the same service attributes. The topic correlation analysis reveals that home like experience and help from the host are associated with Airbnb users' revisit intention. We determine attributes that have the strongest predictive power to Airbnb users' satisfaction and dissatisfaction through the sLDA analysis, which provides valuable managerial insights into priority setting when developing strategies to increase Airbnb users' satisfaction. Methodologically, this study contributes by illustrating how to employ novel approaches to transform social media data into useful knowledge about customer satisfaction, and the findings can provide valuable managerial implications for Airbnb practitioners. (shrink)

We study the degree structure of the ω-c.e., n-c.e., and Π10 equivalence relations under the computable many-one reducibility. In particular, we investigate for each of these classes of degrees the most basic questions about the structure of the partial order. We prove the existence of the greatest element for the ω-c.e. and n-computably enumerable equivalence relations. We provide computable enumerations of the degrees of ω-c.e., n-c.e., and Π10 equivalence relations. We prove that for all the degree classes considered, upward density (...) holds and downward density fails. (shrink)

We give a partial answer to an important open problem in descriptive set theory, the Decomposability Conjecture for Borel functions on an analytic subset of a Polish space to a separable metrizable space. Our techniques employ deep results from effective descriptive set theory and recursion theory. In fact it is essential to extend several prominent results in recursion theory (e.g. the Shore-Slaman Join Theorem) to the setting of Polish spaces. As a by-product we give both positive and negative results on (...) the Martin Conjecture on the degree preserving Borel functions between Polish spaces. Additionally we prove results about the transfinite version as well as the computable version of the Decomposability Conjecture. (shrink)

We study the relationship between effective domination properties and the bounded jump. We answer two open questions about the bounded jump: We prove that the analogue of Sacks jump inversion fails for the bounded jump and the wtt-reducibility. We prove that no c.e. bounded high set can be low by showing that they all have to be Turing complete. We characterize the class of c.e. bounded high sets as being those sets computing the Halting problem via a reduction with use (...) bounded by an ω-c.e. function. We define several notions of a c.e. set being effectively dominant, and show that together with the bounded high sets they form a proper hierarchy. (shrink)

In this paper we show that there is no minimal bound for jump traceability. In particular, there is no single order function such that strong jump traceability is equivalent to jump traceability for that order. The uniformity of the proof method allows us to adapt the technique to showing that the index set of the c.e. strongly jump traceables is image-complete.

In this paper we show that there is a pair of superhigh r.e. degree that forms a minimal pair. An analysis of the proof shows that a critical ingredient is the growth rates of certain order functions. This leads us to investigate certain high r.e. degrees, which resemble ∅′ very closely in terms of ∅′-jump traceability. In particular, we will construct an ultrahigh degree which is cappable.

We show that for every intermediate \ s-degree there exists an incomparable \ s-degree. As a consequence, for every intermediate \ Q-degree there exists an incomparable \ Q-degree. We also show how these results can be applied to provide proofs or new proofs of upper density results in local structures of s-degrees and Q-degrees.

Semi-hyperhypersimple c.e. sets, also known as diagonals, were introduced by Kummer. He showed that by considering an analogue of hyperhypersimplicity, one could characterize the sets which are the Halting problem relative to arbitrary computable numberings. One could also consider half of splittings of maximal or hyperhypersimple sets and get another variant of maximality and hyperhypersimplicity, which are closely related to the study of automorphisms of the c.e. sets. We investigate the Turing degrees of these classes of c.e. sets. In particular, (...) we show that the analogue of a theorem of Martin fails for these classes. (shrink)

We study inversions of the jump operator on ${\mathrm{\Pi }}_{1}^{0}$ classes, combined with certain basis theorems. These jump inversions have implications for the study of the jump operator on the random degrees—for various notions of randomness. For example, we characterize the jumps of the weakly 2-random sets which are not 2-random, and the jumps of the weakly 1-random relative to 0′ sets which are not 2-random. Both of the classes coincide with the degrees above 0′ which are not 0′-dominated. A (...) further application is the complete solution of [24, Problem 3.6.9]: one direction of van Lambalgen's theorem holds for weak 2-randomness, while the other fails. Finally we discuss various techniques for coding information into incomplete randoms. Using these techniques we give a negative answer to [24, Problem 8.2.14]: not all weakly 2-random sets are array computable. In fact, given any oracle X, there is a weakly 2-random which is not array computable relative to X. This contrasts with the fact that all 2-random sets are array computable. (shrink)

We study the relative complexity of equivalence relations and preorders from computability theory and complexity theory. Given binary relationsR,S, a componentwise reducibility is defined byR≤S⇔ ∃f∀x, y[x R y↔fS f].Here,fis taken from a suitable class of effective functions. For us the relations will be on natural numbers, andfmust be computable. We show that there is a${\rm{\Pi }}_1^0$-complete equivalence relation, but no${\rm{\Pi }}_k^0$-complete fork≥ 2. We show that${\rm{\Sigma }}_k^0$preorders arising naturally in the above-mentioned areas are${\rm{\Sigma }}_k^0$-complete. This includes polynomial timem-reducibility on (...) exponential time sets, which is${\rm{\Sigma }}_2^0$, almost inclusion on r.e. sets, which is${\rm{\Sigma }}_3^0$, and Turing reducibility on r.e. sets, which is${\rm{\Sigma }}_4^0$. (shrink)

We show that there is a cuppable c.e. degree, all of whose cupping partners are high. In particular, not all cuppable degrees are${\operatorname {\mathrm {low}}}_3$-cuppable, or indeed${\operatorname {\mathrm {low}}}_n$cuppable for anyn, refuting a conjecture by Li. On the other hand, we show that one cannot improve highness to superhighness. We also show that the${\operatorname {\mathrm {low}}}_2$-cuppable degrees coincide with the array computable-cuppable degrees, giving a full understanding of the latter class.

We study the Turing degrees which contain a real of effective packing dimension one. Downey and Greenberg showed that a c.e. degree has effective packing dimension one if and only if it is not c.e. traceable. In this paper, we show that this characterization fails in general. We construct a real $A\leq_T\emptyset''$ which is hyperimmune-free and not c.e. traceable such that every real $\alpha\leq_T A$ has effective packing dimension 0. We construct a real $B\leq_T\emptyset'$ which is not c.e. traceable such (...) that every real $\alpha\leq_T B$ has effective packing dimension 0. (shrink)

A strong degree of categoricity is a Turing degree [Formula: see text] such that there is a computable structure [Formula: see text] that is [Formula: see text]-computably categorical (there is a [Formula: see text]-computable isomorphism between any two computable copies of [Formula: see text]), and such that there exist two computable copies of [Formula: see text] between which every isomorphism computes [Formula: see text]. The question of whether every [Formula: see text] degree is a strong degree of categoricity has been (...) of interest since the first paper on this subject. We answer the question in the affirmative, by constructing an example. (shrink)

We introduce a natural strengthening of prompt simplicity which we call strong promptness, and study its relationship with existing lowness classes. This notion provides a ≤ wtt version of superlow cuppability. We show that every strongly prompt c.e. set is superlow cuppable. Unfortunately, strong promptness is not a Turing degree notion, and so cannot characterize the sets which are superlow cuppable. However, it is a wtt-degree notion, and we show that it characterizes the degrees which satisfy a wtt-degree notion very (...) close to the definition of superlow cuppability. Further, we study the strongly prompt c.e. sets in the context of other notions related promptness, superlowness, and cupping. In particular, we show that every benign cost function has a strongly prompt set which obeys it, providing an analogue to the known result that every cost function with the limit condition has a prompt set which obeys it. We also study the effect that lowness properties have on the behaviour of a set under the join operator. In particular we construct an array noncomputable c.e. set whose join with every low c.e. set is low. (shrink)

A structure is automatic if its domain, functions, and relations are all regular languages. Using the fact that every automatic structure is decidable, in the literature many decision problems have been solved by giving an automatic presentation of a particular structure. Khoussainov and Nerode asked whether there is some way to tell whether a structure has, or does not have, an automatic presentation. We answer this question by showing that the set of Turing machines that represent automata-presentable structures is ${\rm{\Sigma (...) }}_1^1 $-complete. We also use similar methods to show that there is no reasonable characterisation of the structures with a polynomial-time presentation in the sense of Nerode and Remmel. (shrink)

We prove a number of results in effective randomness, using methods in which Π⁰₁ classes play an essential role. The results proved include the fact that every PA Turing degree is the join of two random Turing degrees, and the existence of a minimal pair of LR degrees below the LR degree of the halting problem.

We study computable Polish spaces and Polish groups up to homeomorphism. We prove a natural effective analogy of Stone duality, and we also develop an effective definability technique which works up to homeomorphism. As an application, we show that there is a $\Delta ^0_2$ Polish space not homeomorphic to a computable one. We apply our techniques to build, for any computable ordinal $\alpha $, an effectively closed set not homeomorphic to any $0^{}$-computable Polish space; this answers a question of Nies. (...) We also prove analogous results for compact Polish groups and locally path-connected spaces. (shrink)

We examine the sequences A that are low for dimension, i.e. those for which the effective dimension relative to A is the same as the unrelativized effective dimension. Lowness for dimension is a weakening of lowness for randomness, a central notion in effective randomness. By considering analogues of characterizations of lowness for randomness, we show that lowness for dimension can be characterized in several ways. It is equivalent to lowishness for randomness, namely, that every Martin-Löf random sequence has effective dimension (...) 1 relative to A, and lowishness for K, namely, that the limit of KA/K is 1. We show that there is a perfect [Formula: see text]-class of low for dimension sequences. Since there are only countably many low for random sequences, many more sequences are low for dimension. Finally, we prove that every low for dimension is jump-traceable in order nε, for any ε > 0. (shrink)

We show that Sacks' and Shoenfield's analogs of jump inversion fail for both tt- and wtt-reducibilities in a strong way. In particular we show that there is a ${\mathrm{\Delta }}_{2}^{0}$ set B > tt ∅′ such that there is no c.e. set A with A′ ≡ wtt B. We also show that there is a ${\mathrm{\Sigma }}_{2}^{0}$ set C > tt ∅′ such that there is no ${\mathrm{\Delta }}_{2}^{0}$ set D with D′ ≡ wtt C.

We describe punctual categoricity in several natural classes, including binary relational structures and mono-unary functional structures. We prove that every punctually categorical structure in a finite unary language is${\text {PA}}(0')$-categorical, and we show that this upper bound is tight. We also construct an example of a punctually categorical structure whose degree of categoricity is$0''$. We also prove that, with a bit of work, the latter result can be pushed beyond$\Delta ^1_1$, thus showing that punctually categorical structures can possess arbitrarily complex (...) automorphism orbits.As a consequence, it follows that binary relational structures and unary structures are not universal with respect to primitive recursive interpretations; equivalently, in these classes every rich enough interpretation technique must necessarily involve unbounded existential quantification or infinite disjunction. In contrast, it is well-known that both classes are universal for Turing computability. (shrink)

The complexity of equivalence relations has received much attention in the recent literature. The main tool for such endeavour is the following reducibility: given equivalence relations R and S on natural numbers, R is computably reducible to S if there is a computable function f:ω→ω that induces an injective map from R-equivalence classes to S-equivalence classes. In order to compare the complexity of equivalence relations which are computable, researchers considered also feasible variants of computable reducibility, such as the polynomial-time reducibility. (...) In this work, we explore Peq, the degree structure generated by primitive recursive reducibility on primitive recursive equivalence relations with infinitely many equivalence classes. In contrast with all other known degree structures on equivalence relations, we show that Peq has much more structure: e.g., we show that it is a dense distributive lattice. On the other hand, we also offer evidence of the intricacy of Peq, proving, e.g., that the structure is neither rigid nor homogeneous. (shrink)

We characterize the linear order types $\tau $ with the property that given any countable linear order $\mathcal {L}$, $\tau \cdot \mathcal {L}$ is a computable linear order iff $\mathcal {L}$ is a computable linear order, as exactly the finite nonempty order types.

We solve a problem posed by Goncharov and Knight 639–681, 757]). More specifically, we produce an effective Friedberg enumeration of computable equivalence structures, up to isomorphism. We also prove that there exists an effective Friedberg enumeration of all isomorphism types of infinite computable equivalence structures.

There are many good reasons to learn about the lives of people who have less social privilege than we do. We might want to understand their circumstances in order to have informed opinions on social policy, or to make our institutions more inclusive. We might also want to cultivate empathy for its own sake. Much of this knowledge is gained through social scientific or humanistic research into others' lives. The entitlement to theorize about or study the lives of marginalized others (...) is often granted under the presumption of academic freedom. This paper will not question whether academic freedom licenses us to do so in the first place ; instead, I will... (shrink)

We propose a signaling pathway in which cell‐extracellular matrix (ECM) adhesion components PINCH‐1 and kindlin‐2 sense mechanical signals from ECM and link them to proline biosynthesis, a vital metabolic pathway for macromolecule synthesis, redox balance, and ECM remodeling. ECM stiffening promotes PINCH‐1 expression via integrin signaling, which suppresses dynamin‐related protein 1 (DRP1) expression and mitochondrial fission, resulting in increased kindlin‐2 translocation into mitochondria and interaction with Δ1‐pyrroline‐5‐carboxylate (P5C) reductase 1 (PYCR1). Kindlin‐2 interaction with PYCR1 protects the latter from proteolytic degradation, (...) leading to elevated PYCR1 level. Additionally, PINCH‐1 promotes P5C synthase (P5CS) expression and P5C synthesis, which, together with increased PYCR1 level, support augmented proline biosynthesis. This signaling pathway is frequently activated in fibrosis and cancer, resulting in increased proline biosynthesis and excessive collagen matrix production, which in turn further promotes ECM stiffening. Targeting this signaling pathway, therefore, may provide an effective strategy for alleviating fibrosis and cancer progression. (shrink)

Since the correct solution to the problem of the relationship between natural science and philosophy is related to the alliance between philosophical workers and natural scientists, it is also related to the development of philosophy and natural science. One of the problems inevitably encountered in solving the problem of the relationship between natural science and philosophy is the materialism of natural science. This article will attempt some theoretical investigation of this problem. Although some of my points may be unsuitable and (...) one-sided, I hope they will be corrected by the natural scientists and philosophical workers. (shrink)

As the twentieth century draws to a close and the rush to globalization gathers momentum, political and economic considerations are crowding out vital ethical questions about the shape of our future. Now, Hans Kung, one of the world's preeminent Christian theologians, explores these issues in a visionary and cautionary look at the coming global society. How can the new world order of the twenty first century avoid the horrors of the twentieth? Will nations form a real community or continue to (...) aggressively pursue their own interests? Will the Machiavellian approaches of the past prevail over idealism and a more humanitarian politics? What role can religion play in a world increasingly dominated by transnational corporations? Kung tackles these and many other questions with the insight and moral authority that comes from a lifetime's devotion to the search for justice and human dignity. Arguing against both an amoral realpolitik and an immoral resurgence of laissez faire economics, Kung defines a comprehensive ethicfounded on the bedrock of mutual respect and humane treatment of all beingsthat would encompass the ecological, legal, technological, and social patterns that are reshaping civilization. If we are going to have a global economy, a global technology, a global media, Kung argues, we must also have a global ethic to which all nations, and peoples of the most varied backgrounds and beliefs, can commit themselves. "The world," he says, "is not going to be held together by the Internet." For anyone concerned about the world we are creating, A Global Ethic for Global Politics and Economics offers equal measures of informed analysis, compassionate foresight, and wise counsel. (shrink)

This paper begins with a contrast between two different views about whether the five sensory consciousnesses are accompanied by vikalpa. For the Abhidharmakośa, the five sensory consciousnesses are accompanied by the svabhāva-vikalpa whose nature is vitarka; but for Yogācāra, the five sensory consciousnesses are without that particular kind of svabhāva-vikalpa because vitarka is regarded as belonging merely to the mental consciousness. My hypothesis for explaining such difference is that Yogācāra assigns that particular kind of svabhāva-vikalpa to mental consciousness rather than (...) to the five sensory consciousnesses. I then look for possible functions of vitarka-vicāra that could map to svabhāva-vikalpa: (a) conceptual vitarka-vicāra in an unconcentrated state; (b) conceptual vitarka-vicāra in a concentrated state; (c) nonconceptual vitarka-vicāra in an unconcentrated state; (d) non-conceptual vitarka-vicāra in a concentrated state. I argue that the svabhāva-vikalpa in the Abhidharmakośa should map to (c) and (d), which in Yogācāra maps to mental perception (mānasapratyakṣa) stipulated by Dignāga. This refers to the discernment of the shape of a cognitive object in the foreground against the background. I end this paper with some general observations about why Yogācāra maps the svabhāvavikapla to the mental consciousness, and about the different senses covered by the Buddhist notion of vikalpa, which is broader than the sense of "conceptualization" as we now understand it. (shrink)

_Buddhist Philosophy of Consciousness_ explores a variety of different approaches to the study of consciousness developed by Buddhist philosophers in classical India and China. It addresses questions that are still being investigated in cognitive science and philosophy of mind.

In the multi-faceted trajectory of post-Kantian thought, Schelling—both the person and his philosophy—has always been a controversial figure. Popular historical accounts focus on his precocious interventions as part of the ‘Jena set’, initially building on Fichte's philosophy of the ‘I’, but quickly coming to challenge his predecessor's philosophical dominance. In the crucial period of the late 1790s, Schelling's most notable intervention was to develop a philosophy of nature alongside the Kantian and Fichtean theories of transcendental subjectivity, which caught the attention (...) of Goethe and led to his appointment, at the age of twenty-three, as professor of philosophy at the University of Jena. But Schelling's life and philosophical work continued well beyond this well-documented period, culminating in a late system in which he developed key ideas surrounding freedom, existence, modality and the history of human consciousness that all revolved around a distinction between what he called negative and positive philosophy. This distinction, and his insistence on the need for the development of the latter mode of philosophy, came to challenge some of the core assumptions of the largely rationalist German idealist project and it remains, to this day, perhaps the most powerful alternative to the Hegelian system that rose to dominance already within Schelling's own lifetime, but also well beyond it. (shrink)

This dissertation argues that the Yogâcāra Buddhism transmitted by the Indian translator Paramârtha (Ch. Zhendi 真諦) underwent a significant transformation due to the influence of his later Chinese interpreters, a phenomenon to which previous scholars failed to paid enough attention. I begin with showing two contrary interpretations of Paramârtha’s notion of jiexing 解性. The traditional interpretation glosses jiexing in terms of “original awakening” (benjue 本覺) in the Awakening of Faith and hence betrays its strong tie to that text. In contrast, (...) a contrary interpretation of jiexing is preserved in a Dunhuang fragment Taishō No. 2805 (henceforth abbreviated as T2805). The crucial part of this dissertation consists in demonstrating that T2805 and the Awakening of Faith represent two competing lineages of the interpreters of Paramârtha. The first clue is that modern scholars have voiced objection to the traditional attribution of the Awakening of Faith to Paramârtha. In addition, I discovered that striking similarities exist between T2805 and Paramârtha’s corpus with respect to terminology, style of phrasing, and doctrine. I further draw attention to the historical testimonies about two different doctrinal views held by Paramârtha’s interpreters. Therefore, I argue that there were two lineages in the name of Paramârtha’s disciples around 590 CE: the indirect lineage interpreted Paramârtha through the lens of the Awakening of Faith; and the direct lineage—represented by T2805—preserved Paramârtha’s original teachings but died out prematurely. Later Chinese Buddhist tradition mistakenly regards the indirect lineage as Paramârtha’s true heir and attributes the Awakening of Faith to Paramârtha. This implies that Paramârtha may have agreed with Xuanzang 玄奘 (600-664) much more than scholars used to assume. For example, Xuanzang’s characterization of the notion of “aboriginal uncontaminated seeds” looks very similar to how Paramârtha depicts jiexing. It also implies that we should distinguish the strong sense of the notion of “tathāgatagarbha” in the Awakening of Faith from its weak sense. The fact that even Vasubandhu endorses the weak sense of “tathāgatagarbha” strongly challenges the received wisdom that Yogâcāra and Tathāgatagarbha were two distinct and antagonistic trends of thought in India. (shrink)

Understanding the meaning of a sentence is crucial for Buddhists because they put so much emphasis on understanding the verbal expressions of the Buddha. But this can be problematic under their metaphysical framework of momentariness, and their epistemological framework of multiple consciousnesses. This paper starts by reviewing the theory of five states of mind in the Yogācārabhūmi, and then investigates debates among medieval East Asian Yogācāra thinkers about how various consciousnesses work together to understand the meaning of a sentence. The (...) major differences between the various explanations proffered lie in the minimum number of types of consciousnesses involved, and the minimum linguistic marks cognized, in order for one to understand a sentence consisting of four Chinese characters. I show that in these disputes, two points are key: First, the role played by the mental consciousness that arises simultaneously with a sensory consciousness: that is to say, whether a sensory consciousness should still be regarded as essential for understanding, if the simultaneous mental consciousness also cognizes the same mark. Second, whether the syntactic structure of a sentence is taken into consideration: that is to say, whether there is a separate determination of understanding regarding each character, or there is no determination until one has heard two or more characters and takes them as a syntactically meaningful unit. (shrink)