We introduce a type theoretical framework in which canon ical term rewriting systems can be represented faithfully both from the logical and the computational points of view The framework is based on congruence types a new syntax which combines inductive algebraic and quotient types Congruence types improve on existing work to combine type theories with algebraic rewriting by making explicit th...

This study has two main aims: (1) analysing the relationship between intellectual capacities and levels of creativity in a sample of Spanish students from the third and sixth grades; and (2) examining the discrimination capacities and degree of congruence among different tests of intellectual ability that are commonly used to identify high-ability students. The study sample comprised 236 primar...

A shear-free ray congruence on Minkowski space is a 3-parameter family of null geodesics along which Lie transport of a complementary 2dimensional spacelike subspace (called the screen space) is conformal. Such congruences are defined by complex analytic surfaces in the associated twistor space CP 3 and are the basis of the construction of massless fields. On a more general space-time, it is un...

OBJECTIVE The ability of alliance to predict outcome has been widely demonstrated, but less is known about the effect of the level of congruence between patient and therapist alliance ratings on outcome. In the current study we examined whether the degree of congruence between patient and therapist alliance ratings can predict symptomatic levels 1 month later in treatment. METHOD The sample c...

We show that noncongruence subgroups of SL2(Z) projectively equivalent to congruence subgroups are ubiquitous. More precisely, they always exist if the congruence subgroup in question is a principal congruence subgroup Γ(N) of level N > 2, and they exist in many cases also for Γ0(N). The motivation for asking this question is related to modular forms: projectively equivalent groups have the sam...

The testing equivalence te that is used as a reference in verification and testing theory in LOTOS is not a congruence, and no explicit definition of the least congruence stronger than te has been found. The critical LOTOS context in which congruence is lost is the hiding context that creates divergence. In this paper we first survey this problem and present three known variants of te that are ...

During the last decade, CCS has been extended in diierent directions, among them priority and real time. One of the most satisfactory results for CCS is Milner's complete proof system for observational congruence 31]. Observational congruence is fair in the sense that it is possible to escape divergence, reeected by the axiom recX:(:X + P) = recX:::P. In this paper we discuss observational cong...

With the proliferation of available electronic service channels for IS users such as mobile or Intranet services in companies, service interactions between IS users and IS professionals have become an increasingly important factor for organizational business-IT alignment. Despite the increasing relevance of such interactions, the implications of agreement or disagreement on the fulfillment of c...