Observational Equivalence Research Articles

Misinformation, observational equivalence and the possibility of rationality

ABSTRACT In vice epistemology, bad epistemic outcomes, such as maintaining false beliefs, are interpreted as indicators of blameworthy irrationality. Conversely, a growing trend in philosophical psychology advocates for environmentalist explanations, suggesting these outcomes emerge because rational cognitive processes of faultless individuals falter due to polluted environmental inputs. Building on concrete examples, I first offer a systematic analysis of the relative explanatory merits of that environmentalist project. I then use this analysis to advance the rationality debate, which has recently been identified as stagnating due to an observational equivalence between environmentalist and vice accounts. Although the conceptual imprecision of vice epistemology has frequently been critiqued, the framework developed here reveals that environmentalism is (also) unable to meet various theoretical desiderata. I show why this is so and argue that, to make progress, environmentalism needs a more substantive conception of epistemic rationality. To this end, I propose that a closer engagement with questions of cognitive agency – how rational creatures can “make up” their minds about what to believe – could enable the necessary progress.

Fully Abstract Encodings of $\lambda$-Calculus in HOcore through Abstract Machines

We present fully abstract encodings of the call-by-name and call-by-value $\lambda$-calculus into HOcore, a minimal higher-order process calculus with no name restriction. We consider several equivalences on the $\lambda$-calculus side -- normal-form bisimilarity, applicative bisimilarity, and contextual equivalence -- that we internalize into abstract machines in order to prove full abstraction of the encodings. We also demonstrate that this technique scales to the $\lambda\mu$-calculus, i.e., a standard extension of the $\lambda$-calculus with control operators.

Retrospective comparison between low-volume high-concentration and high-volume low-concentration levobupivacaine for bilateral erector spinae plane block in dogs undergoing hemilaminectomy

ObjectiveTo compare the analgesic effect of a bilateral ultrasound-guided erector spinae plane block (ESPB) in dogs undergoing hemilaminectomy using either a low-volume high-concentration (LV-HC) or a high-volume low-concentration (HV-LC) local anaesthetic solution. Study designRetrospective observational equivalence trial. AnimalsA total of 391 client-owned dogs undergoing hemilaminectomy. MethodsDogs were assigned to group LV-HC or HV-LC depending on whether 0.2–0.25% levobupivacaine (0.4–0.5 mL kg–1) or 0.125–0.15% levobupivacaine (0.8–1 mL kg–1) was used to perform the ESPB, respectively. The number of dogs in which intraoperative rescue fentanyl boluses were administered, the total dose of fentanyl administered, the overall methadone consumption during the first 24 hours postoperatively and anaesthetic complications were recorded. Univariate and multivariate statistical analyses were performed considering p < 0.05 significant. ResultsA total of 248 and 143 dogs were assigned to groups LV-HC and HV-LC, respectively. In group HV-LC, the number of dogs requiring fentanyl intraoperatively (64.3%) was higher (p = 0.0001) than that in group LV-HC (43.5%). The overall intraoperative fentanyl consumption was higher in group HV-LC between the first skin incision and the end of the lamina drilling (p = 0.028). According to the regression analysis, the group allocation was the best variable to predict the intraoperative fentanyl consumption (p < 0.001).Antimuscarinic drugs were administered more frequently in group LV-HC (p < 0.02). However, the prevalence of hypotension and other pharmacological cardiovascular interventions did not differ between groups. No differences in methadone consumption during the first 24 hours postoperatively were found between the groups. Conclusionsand clinical relevanceWhen performing a bilateral ESPB in dogs undergoing hemilaminectomy, compared with HV-LC, the use of LV-HC local anaesthetic solution reduces the intraoperative fentanyl consumption without affecting the postoperative methadone requirement.

Observational equivalence and security games: Enhancing the formal analysis of security protocols

The formal analysis of security protocols uses abstract language to describe the security protocols, and current protocol descriptions sometimes overlook the security aspects related to cryptographic primitives. In this study, we integrate the security notions of cryptographic primitives with formal methods. Particularly, we use observational equivalence to create security games within the symbolic model. This innovative approach allows for the automation of security detection for cryptographic primitives within the symbolic model. In addition, we have designed and implemented various cryptographic primitives that satisfy different security properties and detect them with our developed security games. The results confirm the effectiveness of our security games. It is worth mentioning that the cryptographic primitives and the characterization of adversary capabilities discussed in this paper can be extended to the formal analysis of other protocols. The ultimate goal is to relax the assumption of perfect encryption and narrow the gap between the formal analysis of security protocols and the real world.

Cross-cultural adaptation and psychometric validation of a Spanish version of the Maryland Assessment of Recovery Scale (MARS-12).

The aim of this study was to adapt and validate a Spanish version of the Maryland Assessment of Recovery Scale (MARS-12). It was carried out in strict accordance with internationally recognized guidelines for test adaptation. A preliminary Spanish version of the MARS-12 was first produced through a standardized translation/back-translation process, ensuring semantic, linguistic, and contextual equivalence with respect to the original scale. Its psychometric properties were then examined in a sample of 325 people with serious mental illness recruited from six different provinces in the Basque Country (northern Spain) and Catalonia (north-eastern Spain). They were users of a total of 20 community rehabilitation and psychiatry services. Confirmatory factor analysis supported a unidimensional structure, consistent with the original scale. Scores on the MARS-12 were positively correlated (.83) with scores on the Questionnaire about the Process of Recovery, supporting convergent validity, while validity evidence based on relationships with other variables was provided by positive correlations between MARS-12 scores and scores on the Dispositional Hope Scale (.82) and on the three dimensions of the Multidimensional Scale of Perceived Social Support (range .30 to .41). Reliability of MARS-12 scores was high (McDonald's ω = .97), as was temporal stability across a one-week interval (.89). The Spanish version of the MARS-12 is a valid and reliable scale that may be used by mental health professionals to assess recovery among Spanish people with serious mental illness.

Asynchronous Probabilistic Couplings in Higher-Order Separation Logic

Probabilistic couplings are the foundation for many probabilistic relational program logics and arise when relating random sampling statements across two programs. In relational program logics, this manifests as dedicated coupling rules that, e.g., say we may reason as if two sampling statements return the same value. However, this approach fundamentally requires aligning or "synchronizing" the sampling statements of the two programs which is not always possible. In this paper, we develop Clutch, a higher-order probabilistic relational separation logic that addresses this issue by supporting asynchronous probabilistic couplings. We use Clutch to develop a logical step-indexed logical relation to reason about contextual refinement and equivalence of higher-order programs written in a rich language with a probabilistic choice operator, higher-order local state, and impredicative polymorphism. Finally, we demonstrate our approach on a number of case studies. All the results that appear in the paper have been formalized in the Coq proof assistant using the Coquelicot library and the Iris separation logic framework.

Efficient Bottom-Up Synthesis for Programs with Local Variables

We propose a new synthesis algorithm that can efficiently search programs with local variables (e.g., those introduced by lambdas). Prior bottom-up synthesis algorithms are not able to evaluate programs with free local variables, and therefore cannot effectively reduce the search space of such programs (e.g., using standard observational equivalence reduction techniques), making synthesis slow. Our algorithm can reduce the space of programs with local variables. The key idea, dubbed lifted interpretation, is to lift up the program interpretation process, from evaluating one program at a time to simultaneously evaluating all programs from a grammar. Lifted interpretation provides a mechanism to systematically enumerate all binding contexts for local variables, thereby enabling us to evaluate and reduce the space of programs with local variables. Our ideas are instantiated in the domain of web automation. The resulting tool, Arborist, can automate a significantly broader range of challenging tasks more efficiently than state-of-the-art techniques including WebRobot and Helena.

Validation of the Family Integration Experience Scale: Chronic Illness for the Portuguese language spoken in Brazil.

to conduct the cross-cultural adaptation and psychometric validation of the Family Integration Experience Scale: Chronic Illness in Brazilian Portuguese. a methodological study divided into two stages. In the first stage, the Family Integration Experience Scale: Chronic Illness was cross-culturally adapted for Brazilian culture, when the scale was subjected to translations, back-translations, and a committee of judges - to verify the semantic, linguistic, and contextual equivalence between the original and translated items. The second step was to validate the scale in a sample of families of children and adolescents with chronic illnesses. The participants were 230 families of children with chronic illnesses attending the outpatient clinic of a tertiary public hospital with teaching and research characteristics. internal consistency was tested using Cronbach's alpha (0.81) and McDonald's omega (0.81). Confirmatory factor analysis was also tested, and the model's fit was acceptable for validation standards. the version of the Family Integration Experience Scale: Chronic Illness showed evidence of validation and can be considered a valid and reliable instrument in Brazilian culture. The Brazilian Portuguese version of the Family Integration Experience Scale: Chronic Illness can be used to measure the experience of family integration in chronic illness.

TRANSLATOR'S HABITUS AND TRANSLATION IDEOLOGY: TRANSLATING THE CONCEPT OF CAPITALS IN THE NOVEL BUMI MANUSIA BY PRAMOEDYA ANANTA TOER

This study examines the relationship between the translator's habitus and translation ideology in translating the concept of capitals that exists in the two main characters in the novel Bumi Manusia by Pramoedya Ananta Toer. This research uses a descriptive qualitative method by taking a case study of two chapters in Bumi Manusia and its translation in English. The study found 30 expressions containing modals in the two main characters in chapters 5 and 7. The translation procedures carried out by the translator consist of standard translation (one datum), transference (15 data), modulation (four data), literal (six data), addition (one datum), contextual equivalence (two data), and paraphrasing (one datum). From Minke's character, there were 11 translations with the ideology of domestication and seven data of foreignization; and from Nyai Ontosoroh's character, only one expression that was translated domestically, and the other 11 data were foreignized. Therefore, 12 out of 30 data, i.e., 40%, were translated with domestication ideology, while 18 out of 30 data or 60% were translated with foreignization ideology. In conclusion, a translator's habitus influenced his way of translating which automatically directed his translation ideology.

Roll-call voting under random seating assignment

AbstractSocial connections between individuals can profoundly impact their political behavior. A growing body of research on legislative politics examines how spatial proximity to fellow legislators affects voting behavior within the institution. However, studies that examine this question often suffer from a fundamental identification problem in which proximity effects may reflect actual behavioral diffusion between members or, instead, homophily, in which legislators of a similar political feather flock together. We overcome this observational equivalence by exploiting a unique random seating lottery for seating assignments in the world's oldest existing parliament, Iceland's national legislature, Alþingi. Utilizing this naturally occurring randomization, we employ spatial analyses of more than 20,000 estimates of spatial dependence and find little evidence that seating proximity leads to similar voting behavior by members in this legislative context.

A General Fine-Grained Reduction Theory for Effect Handlers

Effect handlers are a modern and increasingly popular approach to structuring computational effects in functional programming languages. However, while their traditional operational semantics is well-suited to implementation tasks, it is less ideal as a reduction theory. We therefore introduce a fine-grained reduction theory for deep effect handlers, inspired by our existing reduction theory for shift0, along with a standard reduction strategy. We relate this strategy to the traditional, non-local operational semantics via a simulation argument, and show that the reduction theory preserves observational equivalence with respect to the classical semantics of handlers, thus allowing its use as a rewriting theory for handler-equipped programming languages -- this rewriting system mostly coincides with previously studied type-based optimisations. In the process, we establish theoretical properties of our reduction theory, including confluence and standardisation theorems, adapting and extending existing techniques. Finally, we demonstrate the utility of our semantics by providing the first normalisation-by-evaluation algorithm for effect handlers, and prove its soundness and completeness. Additionally, we establish non-expressibility of the lift operator, found in some effect-handler calculi, by the other constructs.

Program equivalence in a typed probabilistic call-by-need functional language

We extend a call-by-need variant of PCF with a binary probabilistic fair choice operator, which makes a lazy and typed variant of probabilistic functional programming. We define a contextual equivalence that respects the expected convergence of expressions and prove a corresponding context lemma. This enables us to show correctness of several program transformations with respect to contextual equivalence. Distribution-equivalence of expressions of numeric type is introduced. While the notion of contextual equivalence stems from program semantics, the notion of distribution equivalence is a direct description of the stochastic model. Our main result is that both notions are compatible: We show that for closed expressions of numeric type contextual equivalence and distribution-equivalence coincide. This provides a strong and often operationally feasible criterion for contextual equivalence of expressions and programs.

High Discounts and Low Fundamental Surplus: An Equivalence Result for Unemployment Fluctuations

We establish an observational equivalence between unemployment fluctuations of the Diamond-Mortensen-Pissarides search economy augmented with time varying risk premia and an otherwise identical economy without risk premia but with a time varying value of leisure. This equivalence holds for general risk premia processes and allows us to view the effects of different models of risk premia as operating through a single channel—one that alters the value of leisure. We derive simple expressions for semielasticities of labor market tightness with respect to productivity and risk premium shocks. We show wages can be used to detect misspecification in the discount rate process used in hiring decisions. This paper was accepted by Lukas Schmid, finance. Supplemental Material: The online appendix is available at https://doi.org/10.1287/mnsc.2022.03712 .

Observational Equivalence of Conditional Belief Bases

In nonmonotonic reasoning, a conditional of the form ‘If A then usually B’ is typically accepted if a situation where both A and B hold is deemed to be more plausible, more probable, or less surprising, etc., than a situation where A holds, but B does not hold. In a propositional setting, this leads to a relation on the propositional interpretations, also called worlds, by comparing worlds according to their plausibility. In this paper, we address the question of which kind of relations on the set of worlds can be obtained by completing a conditional belief base via an inductive inference operator. As a key concept for our investigations, we introduce and employ the notion of observational equivalence of belief bases that takes an inductive inference operator and a set of queries into account. This leads to the notion of the observational normal form (ONF) and, by focussing on so-called base conditionals, to the base conditional normal form (BCNF). The acceptance of base conditionals corresponds to the plausibility ordering on possible worlds induced by an inference method. Both normal forms ONF and BCNF are combined with renamings as an additional dimension. We establish the interrelationships among the normal forms and evaluate them empirically with respect to systematically generated belief bases.

Identifying the source of information rigidities in the expectations formation process

Coibion and Gorodnichenko (2015) provide a useful framework to test the null hypothesis of full-information rational expectations against two popular classes of information rigidities, sticky information (SI) and noisy information (NI). However, the observational equivalence of SI and NI in average forecast errors gives no power in the test for one against the other. We identify the source of information rigidities by estimating the equations for the average forecast errors and variance of forecasts. The results show the importance of both SI and NI, but favor a type of NI in which agents can quickly learn the underlying state.

Contextuality with Disturbance and without: Neither Can Violate Substantive Requirements the Other Satisfies.

Contextuality was originally defined only for consistently connected systems of random variables (those without disturbance/signaling). Contextuality-by-Default theory (CbD) offers an extension of the notion of contextuality to inconsistently connected systems (those with disturbance) by defining it in terms of the systems' couplings subject to certain constraints. Such extensions are sometimes met with skepticism. We pose the question of whether it is possible to develop a set of substantive requirements (i.e., those addressing a notion itself rather than its presentation form) such that (1) for any consistently connected system, these requirements are satisfied, but (2) they are violated for some inconsistently connected systems. We show that no such set of requirements is possible, not only for CbD but for all possible CbD-like extensions of contextuality. This follows from the fact that any extended contextuality theory T is contextually equivalent to a theory T' in which all systems are consistently connected. The contextual equivalence means the following: there is a bijective correspondence between the systems in T and T' such that the corresponding systems in T and T' are, in a well-defined sense, mere reformulations of each other, and they are contextual or noncontextual together.

Foundering on fallacies: theorizing the Eurozone’s self-harming mercantilism

The Eurozone’s export-oriented policy regime and pursuit of trade surpluses remains thoroughly puzzling. Rooted in overly strict fiscal policies, inequality and underinvestment; undermining growth and contributing to trade tensions– it defies economic self-interest. This paper develops an analytical framework to confront this puzzle. It argues that these policies are self-harming, but are nonetheless pursued, because of three fallacies that obscure the cost-benefit calculus attached to them. These fallacies are rooted in the empirical problem of observational equivalence: the same observed surplus can be driven by different underlying processes, and its net benefit will depend on our assumptions about these drivers. The first fallacy is mistaking external enablers for domestic competitiveness—interpreting export success to be linked to domestic reform, when it was largely explained by better links to faster growing trading partners. The second fallacy is mistaking weak imports for strong exports—interpreting surpluses as ‘winning’, even when they are not driven by superior exports but sluggish imports. The third fallacy is mismeasuring multinational firms’ contributions to national exports—interpreting profit shifting and assets stashed in low tax jurisdictions as export performance. Germany and Ireland, as paradigmatic ‘success cases of austerity’, are used to expand the argument.

Using arbitrary precision arithmetic to sharpen identification analysis for DSGE models

SummaryWe introduce arbitrary precision arithmetic to resolve practical difficulties arising in the identification analysis of dynamic stochastic general equilibrium (DSGE) models. A three‐step procedure is proposed to address local and global identification and the empirical distance between models. The method is applied to monetary and fiscal policy interaction models, revealing exact observational equivalence in a small‐scale model between an indeterminate passive monetary and fiscal policy regime and determinate regimes, and near observational equivalence in a medium‐scale model. Additionally, the method yields new insights for a model with news shocks, demonstrating that wage markup shocks can be replaced by unanticipated moving average shocks, resulting in near observational equivalence.

A Core Calculus for Equational Proofs of Cryptographic Protocols

Many proofs of interactive cryptographic protocols (e.g., as in Universal Composability) operate by proving the protocol at hand to be observationally equivalent to an idealized specification. While pervasive, formal tool support for observational equivalence of cryptographic protocols is still a nascent area of research. Current mechanization efforts tend to either focus on diff-equivalence, which establishes observational equivalence between protocols with identical control structures, or require an explicit witness for the observational equivalence in the form of a bisimulation relation. Our goal is to simplify proofs for cryptographic protocols by introducing a core calculus, IPDL, for cryptographic observational equivalences. Via IPDL, we aim to address a number of theoretical issues for cryptographic proofs in a simple manner, including probabilistic behaviors, distributed message-passing, and resource-bounded adversaries and simulators. We demonstrate IPDL on a number of case studies, including a distributed coin toss protocol, Oblivious Transfer, and the GMW multi-party computation protocol. All proofs of case studies are mechanized via an embedding of IPDL into the Coq proof assistant.

Step-Indexed Logical Relations for Countable Nondeterminism and Probabilistic Choice

Developing denotational models for higher-order languages that combine probabilistic and nondeterministic choice is known to be very challenging. In this paper, we propose an alternative approach based on operational techniques. We study a higher-order language combining parametric polymorphism, recursive types, discrete probabilistic choice and countable nondeterminism. We define probabilistic generalizations of may- and must-termination as the optimal and pessimal probabilities of termination. Then we define step-indexed logical relations and show that they are sound and complete with respect to the induced contextual preorders. For may-equivalence we use step-indexing over the natural numbers whereas for must-equivalence we index over the countable ordinals. We then show than the probabilities of may- and must-termination coincide with the maximal and minimal probabilities of termination under all schedulers. Finally we derive the equational theory induced by contextual equivalence and show that it validates the distributive combination of the algebraic theories for probabilistic and nondeterministic choice.