In a perfect category every object has a minimal projective resolution. We give a sufficient condition for the category of modules over a category-graded algebra to be perfect. AMS Subject Classification (2000): 18E15, 16W50. In [6] the second author explored homological properties of algebras graded over a small category. Our interest in these algebras arose from our research on the homologica...

Projective techniques are unusual and often intriguing for respondents to complete, permitting them to express thoughts and feelings which can be difŽ cult to access by direct and structured questioning. This is achieved by presenting respondents with ambiguous verbal or visual stimulus materials, such as bubble cartoons, which they need to make sense of by drawing from their own experiences, t...

This paper examines a newly created approach to exploring travel motivations, the Travel Career Patterns (TCP) model. Through an analysis of the TCP model, the authors advance travel motivation theory by making three contributions: a refinement of the definition of travel experience; the use and evaluation of essays as a qualitative tool for interpreting travel motives; and an extension of the ...

Misattributions people make about their own affective reactions can be used to measure attitudes implicitly. Combining the logic of projective tests with advances in priming research, the affect misattribution procedure (AMP) was sensitive to normatively favorable and unfavorable evaluations (Experiments 1-4), and the misattribution effect was strong at both fast and slow presentation rates (Ex...

Logically, though not historically, projective techniques must be regarded as a part of the general field of psychological measurement. Projective testing and research may therefore legitimately be studied within the theoretical and methodologicall framework of psychological measurement, always keeping in mind, of course, the problems that are peculiar to projective techniques. Largely as a.. r...

We prove that in an abelian category with enough projective objects, the extension subcategory of two covariantly finite subcategories is still covariantly finite. This extends a result by Sikko and Smalø. We also prove a triangulated version of the result. As applications, we obtain short proofs to a classical result by Ringel and a recent result by Krause and Solberg. 1. Main Theorems Let C b...

The study of finite projective planes involves planar functions, namely, functions f : Fq → Fq such that, for each a ∈ F ∗ q , the function c 7→ f(c + a) − f(c) is a bijection on Fq. Planar functions are also used in the construction of DES-like cryptosystems, where they are called perfect nonlinear functions. We determine all planar functions on Fq of the form c 7→ c , under the assumption tha...

(Algebra) It’s a complex projective manifold C of dimension one. As such, it has a field of rational functions K(C) of transcendence degree one over the field C of scalars. The curve can be recovered from the field as the set of discrete valuation rings of K/C, which has the “natural” structure of a projective manifold. There is a canonical line bundle ωC , whose degree captures the genus via d...