Union Types Research Articles

Cross-Border Unions: Internationals in Canada, 1901–1914

Debate on the role of international unions (unions with headquarters in the United States) in Canada is longstanding. One school of thought maintains that internationals have weakened Canada's union movement; another view holds that international and national unions acted in concert and increased the number of disputes and the likelihood of workers' victory. Using a newly created data base of strike dimensions for the period before World War I, the key years of union growth in Canada, we test these opposing views in a competing-risks framework. We find that internationals did not weaken Canada's union movement; nor did the two union types act in concert. Instead, internationals were absorbed in Canada's industrial relations framework.

Consensual Unions In Two Costa Rican Communities: An Analysis Using Focus Group Methodology

This study uses focus groups to explore the nature of consensual unions and the relationship between union type and fertility in Costa Rica. Participants, both men and women, were drawn from two communities, La Cruz in the province of Guanacaste, and Cahuita, in the province of Limon. I hypothesize that women’s status, reflecting gender differences in power distribution, is an important determinant of the type of union chosen. Women with a weaker “bargaining position” in their relationships with men (reflected in their socioeconomic status, children from previous unions, age, etc.) are more likely to enter consensual than legal unions, which offer less legal and financial protection. The weaker “bargaining position” of women in consensual unions in turn is likely to affect the “marital relationship" so that women in consensual unions may have less say in fertility decisions than their partners. The results show that while most respondents state that there are no differences between union types in terms of family obligations and responsibilities, women are nevertheless aware that consensual unions may end up providing them with little legal or financial support, and that they and their children risk being left on their own. The greater instability of the consensual union influences fertility in that women appear to use children to create a securer bond within such unions. Further work in this area would benefit from more research into the cultural context within which decisions regarding union formation are made and the constraints on union choice.

Optimal Representations of Polymorphic Types with Subtyping

Many type inference and program analysis systems include notions of subtyping and parametric polymorphism. When used together, these two features induce equivalences that allow types to be simplified by eliminating quantified variables. Eliminating variables both improves the readability of types and the performance of algorithms whose complexity depends on the number of type variables. We present an algorithm for simplifying quantified types in the presence of subtyping and prove it is sound and complete for non-recursive and recursive types. We also show that an extension of the algorithm is sound but not complete for a type language with intersection and union types, as well as for a language of constrained types.

Does marriage require a stronger economic underpinning than informal cohabitation?

A large proportion of cohabitors in the Statistics Norway Omnibus Surveys of 1996 reported economic reasons for their hesitation to marry, and in particular the costs of the wedding. In line with this, the Norwegian Family and Occupation Survey of 1988 revealed effects both of women's cumulated income and men's non-employment on the actual choice of union type. Also some other evidence suggests that affordability matters, although there are plausible alternative interpretations. On the other hand, several estimates suggest that economic strength does not induce marriage. Since there also has been no deterioration of young adults' economic situation in Norway, except for the delay of economic independence owing to longer college enrolment, one can hardly claim that lack of affordability is a dominating force behind the massive drift away from marriage. The analysis is anchored in a theoretical framework that may prove useful in other studies of cohabitation as an alternative to marriage.

Union Responses to Nafta in the US and Canada: Explaining Intra- and International Variation

In this article we ask why some unions in Canada and the United States were more actively opposed to NAFTA than others, and why these "activist" unions differed in the strategies that they adopted for fighting NAFTA and in the alternatives that they offered to it. We ask the same questions about differences between the U.S. and Canadian labor movements as embodied in the rhetoric and behavior of their central federations. We distinguish four union "types" on two dimensions: the inclusiveness of union leaders' collective identity (i.e., the kinds of workers that the union actively seeks to organize), and the radicalness of union leaders' moral economy (i.e., how critical the union is of the status quo political economy). We hypothesize that differences in union type, so defined, explain a significant part of the variation in the levels of union activism against NAFTA in both countries, as well as differences in strategies of opposition. Differences in the relative strength of union types is also hypothesized to be an important factor explaining strategic differences between the two national labor federations. We use statistical analysis of survey data, as well as qualitative analysis of institutional variables, to operationalize and assess these hypotheses. We find considerable support for them.

A Filter Model for Concurrent $\lambda$-Calculus

Type-free lazy $\lambda$-calculus is enriched with angelic parallelism and demonic nondeterminism. Call-by-name and call-by-value abstractions are considered and the operational semantics is stated in terms of a must convergence predicate. We introduce a type assignment system with intersection and union types, and we prove that the induced logical semantics is fully abstract.

Enhancement of fracture healing by mechanical and surgical intervention.

Mechanical modulation of bone fracture repair and restoration to its structural strength must rely on the fundamental physical concept of remodeling according to the type of stress applied to immature or undifferentiated tissue. This article proposes the possible mechanisms of interaction between physical factors and cellular responses in healing long bone fractures and speculates on the advantages and limitations of different experimental models in evaluating these interactions. A revised classification system of fracture union types based on histomorphologic characteristics is introduced here as a reference standard in the studies of possible accelerating factors. Bone fracture union can follow more than one or two pathways, with various combinations of bone formation mechanisms, whereas there may be only one bone remodeling principle. There are definite mechanical and operative interventions that can provide effective enhancement to fracture healing. However, different intervention may limit its association to a specific healing mechanism. The key element in establishing these interactions is defining the precise cellular and molecular mechanisms in a quantitative manner. This can be achieved best by interdisciplinary research collaborations working on a higher level of expertise in each related field using standardized experimental models. Not only a basic understanding of the associated cellular reactions is necessary, but also the specific forms of mechanical stimulation, the dose effect, and its application timing must be determined and validated. Without this basic research effort, it would be difficult to transform such an augmentational modality into effective and reliable therapeutic regimens for clinical application. Furthermore, successful fracture repair enhancement must have proper new bone formation maintenance and remodeling through physiologic loading, or the initial stimulation process may be short lived and unable to reestablish the required biomechanical strength of the long bone. Finally, there is no substitute for a well organized and carefully controlled prospective clinical trial in establishing the validity of any bone fracture healing enhancement modality, regardless of its nature and form of application.

A Discriminant Analysis of Employee Choice in a Multiunion Representation Election

AbstractThe study of union certification elections is well advanced in the academic literature. There is, however, little research on determinants of union certification when more than one union is on the ballot. The work on multiunion elections that does exist is primarily descriptive and conducted at the macro level. This paper presents a micro‐level study of a multiunion election. Three sets of variables derived from expectancy theory, the investments model, and the theory of reasoned action, were posited to influence employee choice in a multiunion election. Data were collected via a mail survey of 270 employees who recently participated in a multiunion election. The data were analyzed using multiple analysis of variance and discriminant analysis. The results provide strong evidence that the employee vote in a multiunion election is correlated with (a) an evaluation of the efficacy of a raiding union, (b) employee behavioural investments, and (c) the attitudes of others in the immediate work group. Implications for labour practitioners centre on increasing employee involvement, identifying the union with important others, and delivering desired results. Future researchers may wish to extend this framework to other settings.RésuméL'analyse des élections pour Vaccréditation syndicale est un sujet souvent traité dans les revues savantes. Cependant, on n'a que peu etudié les facteurs qui déterminent Vaccréditation en cas de syndicats multiples dans un scrutin. II existe surtout jusqu'à ce jour des descriptions ou des macroanalyses. Cet article présente une microanalyse d'une élection multisyndicale, prenant pour principe que trois ensembles de variables influencent le choix des employés: des variables inspirées par la Théorie des attentes (Expectancy Theory), par le Modèle des investisse‐ments et par la Théorie de Vaction raisonnée (Reasoned Action Theory). Un sondage par correspondence de 270 employés, qui avaient récemment participé à une élection à syndicats multiples, a foumi les données qui ont servi de base pour une analyse de variance et de discrimination. Les resultats indiquent clairement une corrélation entre le vote de l'employé et (1) l'évaluation de l'éfficacité d'un syndicat agresseur (raiding union), (2) les investissements com‐portementaux de l'employé, et (3) les attitudes des col‐lègues dans le groupe de travail. Pour qu'un syndicat puisse préserver son accréditation, ces résultats lui sug‐gèrent d'augmenter la participation des employés qu'il représente, d'encourager la loyauté des employés ay ant une influence sur leurs collègues, et d'améliorer la performance des services de base pour employés. De futures recherches pourront éStendre ce cadre á d'autres contextes.

The "Relevance" of Intersection and Union Types

The aim of this paper is to investigate a Curry-Howard interpre- tation of the intersection and union type inference system for Combinatory Logic. Types are interpreted as formulas of a Hilbert-style logic L, which turns out to be an extension of the intuitionistic logic with respect to provable dis- junctive formulas (because of new equivalence relations on formulas), while the implicational-conjunctive fragment of L is still a fragment of intuitionistic logic. Moreover, typable terms are translated in a typed version, so that ∨-∧- typed combinatory logic terms are proved to completely codify the associated logical proofs.

A practical soft type system for scheme

Asoft type systeminfers types for the procedures and data structures of dynamically typed programs. Like conventional static types, soft types express program invariants and thereby provide valuable information for program optimization and debugging. A soft typecheckeruses the types inferred by a soft type system to eliminate run-time checks that are provably unnecessary; any remaining run-time checks are flagged as potential program errors.Soft Schemeis a practical soft type checker for R4RS Scheme. Its underlying type system generalizes conventional Hindley-Milner type inference by incorporating recursive types and a limited form of union type. Soft Scheme accommodates all of R4RS Scheme including uncurried procedures of fixed and variable arity, assignment, and continuations.

Filter models for conjunctive-disjunctive λ-calculi

The distinction between the conjunctive nature of non-determinism as opposed to the disjunctive character of parallelism constitutes the motivation and the starting point of the present work. λ-calculus is extended with both a non-deterministic choice and a parallel operator; a notion of reduction is introduced, extending β-reduction of the classical calculus. We study type assignment systems for this calculus, together with a denotational semantics which is initially defined constructing a set semimodel via simple types. We enrich the type system with intersection and union types, dually reflecting the disjunctive and conjunctive behaviour of the operators, and we build a filter model. The theory of this model is compared both with a Morris-style operational semantics and with a semantics based on a notion of capabilities.

A Shortage of Marriageable Men? A Note on the Role of Cohabitation in Black-White Differences in Marriage Rates

Using the National Survey of Families and Households, the author explores the role of cohabitation in differences between Blacks and Whites in union formation. Previous research has explained at most one-quarter of racial differences in marriage rates. Despite this and a well-documented rise in premarital cohabitation among both races, no previous research has explored racial differences in union formation. He begins by showing that the Black-White difference in the timing of first union (that is, first cohabitation or first marriage) is about one-half the Black-White difference in the timing of first marriage. Then he uses proportional hazard models to determine whether racial differences in first union formation rates and first union type can be attributed to the availability of men or to men's employment characteristics. The results provide clear evidence that marriage market characteristics contribute to the lower likelihood that Black women will cohabit or will marry. However, Black-White differences in union type (that is, the greater tendency among Blacks to cohabit rather than to marry) are not related to differences in the availability of employed men

Filter models for conjunctive-disjunctive λ-calculi

The distinction between the conjunctive nature of non-determinism as opposed to the disjunctive character of parallelism constitutes the motivation and the starting point of the present work. λ-calculus is extended with both a non-deterministic choice and a parallel operator; a notion of reduction is introduced, extending β-reduction of the classical calculus. We study type assignment systems for this calculus, together with a denotational semantics which is initially defined constructing a set semimodel via simple types. We enrich the type system with intersection and union types, dually reflecting the disjunctive and conjunctive behaviour of the operators, and we build a filter model. The theory of this model is compared both with a Morris-style operational semantics and with a semantics based on a notion of capabilities.

Areal and socioeconomic differentials in infant and child mortality in Cameroon

Given its geographical, socio-economic, ethnic and cultural diversity, Cameroon offers an excellent setting for investigating the contribution of geographical and socioeconomic factors to mortality differences in infancy and childhood. Such research is crucial for designing appropriate health policies at the national and regional levels. Using data from a nationally representative sample of more than 12,000 births, this study assesses infant and child mortality differences in Cameroon by residence area, mother's education, ethnicity, marital status and union type, religion and the interplay of those factors on differentials mortality. The most vulnerable groups of children in the country are: rural residents; residents of the East, North and South-West regions; Kaka-Baya and Fulbe-Fulani children; and children whose mothers have no education, are Traditionalists, are unmarried, or are in polygamous unions. Lack of maternal schooling alone explains all the excess childhood mortality of Fulbe-Fulani children, most of the excess mortality of children of the North and East regions, most of the excess mortality of the countryside vis-à-vis the metropolitan areas of Yaoundé and Douala, and most of the excess mortality of children of Traditionalists. The robustness of the excess neonatal mortality of newborns in the East region probably reflects the higher prevalence of tetanus in that region compared to the rest of the country. The study also suggests that the place/region of residence in Cameroon is likely to be a proxy for inequalities in the provision of and/or use of health services.

Intersection and Union Types: Syntax and Semantics

Type assignment systems with intersection and union types are introduced. Although the subject reduction property with respect to β-reduction does not hold for a natural deduction-like system, we manage to overcome this problem in two, different ways. The first is to adopt a notion of parallel reduction, which is a refinement of Gross-Knuth reduction. The second is to introduce type theories to refine the system, among which is the theory called Π that induces an assignment system preserving β-reduction. This type assignment system further clarifies the relation with the intersection discipline through the decomposition, first, of a disjunctive type into a set of conjunctive types and, second, of a derivation in the new type assignment system into a set of derivations in the intersection type assignment system. For this system we propose three semantics and prove soundness and completeness theorems.

Migration and Union Dissolution among Puerto Rican Women

The aim was to examine the impact of migration on family formation and dissolution among mainland Puerto Ricans at the individual level. Aggregate data have shown significant effects of residential mobility and migration on divorce but operational mechanisms have not been identified. Data for this study were obtained from pooled life history data on Puerto Rican women aged 15-49 years in the US and Puerto Rico available from the 1982 Puerto Rican Fertility and Family Planning Assessment and the 1985 New York Fertility Employment and Migration Survey. Retrospective event histories provided data on cohabitation marriage fertility education employment and migration. Migration is taken to be time varying: nonmigrants return migrants first generation US migrants second generation US residents and US-born return migrants. Union dissolution behavior is analyzed for each status group in multivariate models. The assumption was that differences among status groups in divorce may be due to factors other than migration. Religion number of siblings and mothers age at first birth were included as background variables. Other factors at the start of the union were womans age preunion births union type education and employment experience. Time varying respondent attributes were union type employment and number and ages of children born within the union. The results support prior individual level theories. Puerto Rican women who had early union formation were pregnant at the start of coresidence and had a preunion birth were more likely to have disruption. Employment was also a contributing factor if the woman did not work prior to union formation. Social integration and support also affected union stability. Life tables showed that nonmigrants had the lowest proportion experiencing disruption and disruption rose with exposure to the US. Logistic regressions confirmed the differences between migrants and nonmigrants. The rate of disruption was 50% lower among women who entered legal marriage and the presence of young children <6 years reduced the likelihood of union disruption. The rate of disruption was 57% more likely among women who migrated during the previous year and particularly high among recent migrants in informal unions.

Combining type disciplines

We present a type inference system for pure λ-calculus which includes, in addition to arrow types, also universal and existential type quantifiers, intersection and union types, and type recursion. The interest of this system lies in the fact that it offers a possibility to study in a unified framework a wide range of type constructors. We investigate the main syntactical properties of the system, including an analysis of the preservation of types under parallel reduction strategies, leading to a form of the subject-reduction property. We describe a model for this system where types are special subsets of a D∞ model for λ-calculus, without imposing any formal contractiveness constraint on types of the kind considered for a closely related system by MacQueen, Plotkin and Sethi (1986).

Singleton, Union, and Intersection Types for Program Extraction

Two types theories, ATT and ATTT, are introduced. ATT is an impredicative type theory closely related to the polymorphic type theory of implicit typing of MacQueen et al . ((1986), Inform. and Control 71 , 95-130). ATTT is another version of ATT that extends the Girard-Reynolds second order lambda calculus. ATT has notions of intersection, union, and singleton types. ATTT has a notion of refinement types as in the type system for ML by Freeman and Pfenning ((1991), in "ACM SIGPLAN ′91," ACM Press), plus intersection and union of refinement types and singleton refinement types. We will show how singleton, union, and intersection types serve for development of programs without unnecessary codes via a variant of the Curry-Howard isomorphism. More exactly, they give a way to write types as specifications of programs without the unnecessary codes which are inevitable in the usual Curry-Howard isomorphism.

Inhabitation in Intersection and Union Type Assignment Systems

Inhabitation in Intersection and Union Type Assignment Systems

A quick introduction to the programming language MIKE

MIKE is a new programming language developed by the author as a base language for the development of algebraic and symbolic algorithms. It is a structured programming language with a MODULA-2-like syntax supporting special features such as transparent dynamic memory management, discriminated union types, operator overloading, data abstraction and parametrized types. This text gives an overview of the main features of the language as of version 2.0.