Displaying similar documents to “Algebraic theory of stacks”

Weakly additive cohomology.

Edwin Spanier (1990)

Publicacions Matemàtiques

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In this paper the concept of weakly additive cohomology theory is introduced as a variant of the known concept of additive cohomology theory. It is shown that for a closed A in X the singular homology of the pair (X, X-A) (with some fixed cohomology group) regarded as a furcter of A is a weakly additive cohomology theory on any collectionwise normal space X. Furthermore, every compactly supported cohomology theory is weakly additive. The main result is a comparison theorem...

On the lattice of additive hereditary properties of finite graphs

Ján Jakubík (2002)

Discussiones Mathematicae - General Algebra and Applications

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In this paper it is proved that the lattice of additive hereditary properties of finite graphs is completely distributive and that it does not satisfy the Jordan-Dedekind condition for infinite chains.

Clans

Oswald Wyler (1965-1966)

Compositio Mathematica

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Prime ideals in the lattice of additive induced-hereditary graph properties

Amelie J. Berger, Peter Mihók (2003)

Discussiones Mathematicae Graph Theory

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An additive induced-hereditary property of graphs is any class of finite simple graphs which is closed under isomorphisms, disjoint unions and induced subgraphs. The set of all additive induced-hereditary properties of graphs, partially ordered by set inclusion, forms a completely distributive lattice. We introduce the notion of the join-decomposability number of a property and then we prove that the prime ideals of the lattice of all additive induced-hereditary properties are divided...