منابع مشابه
An Approximation Theorem for Maps into Kan Fibrations
This theorem has an interesting special case. Take X = E a Kan set, Y = S\E\, B a point, p, h the unique constant maps, / = idEf i the natural inclusion and g the natural retraction. What comes out is the famous Milnor-Lamotke theorem saying E is strong deformation retract of S\E\. Thus we get a new proof of this theorem which in contrast to the original one [4] avoids any reference to J.H.C. W...
متن کاملFibrations, Compactifications and Algebras of Pseudodifferential Operators
Some recent, and some new, results on the structure of algebras of pseudodiierential operators on compact manifolds with boundary are discussed. In particular their relationship to compactiications of non-compact spaces is emphasized. It is shown how these relationships allow the methods of pseudodierential operators (\microlocalization") to be applied to problems in scattering and spectral the...
متن کاملDeciding some Maltsev conditions in finite idempotent algebras
In this paper we investigate the computational complexity of deciding if a given finite algebraic structure satisfies a certain type of existential condition on its set of term operations. These conditions, known as Maltsev conditions, have played a central role in the classification, study, and applications of general algebraic structures. Several well studied properties of equationally define...
متن کاملMaltsev on Top
Let A be an idempotent algebra, α ∈ ConA such that A/α has few subpowers, and m be a fixed natural number. There is a polynomial time algorithm that can transform any constraint satisfaction problem over A with relations of arity at most m into an equivalent problem which is m consistent and in which each domain is inside an α block. Consequently if the induced algebras on the blocks of α gener...
متن کاملOn Maltsev Digraphs
We study digraphs preserved by a Maltsev operation: Maltsev digraphs. We show that these digraphs retract either onto a directed path or to the disjoint union of directed cycles, showing in this way that the constraint satisfaction problem for Maltsev digraphs is in logspace, L. We then generalize results from Kazda (2011) to show that a Maltsev digraph is preserved not only by a majority opera...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: gmj
سال: 2002
ISSN: 1572-9176,1072-947X
DOI: 10.1515/gmj.2002.71