Displaying similar documents to “Pointwise and global sums and negatives of binary relations.”

Fundamental pro-groupoids and covering projections

Luis Hernández-Paricio (1998)

Fundamenta Mathematicae

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We introduce a new notion of covering projection E → X of a topological space X which reduces to the usual notion if X is locally connected. We use locally constant presheaves and covering reduced sieves to find a pro-groupoid π crs (X) and an induced category pro (π crs (X), Sets) such that for any topological space X the category of covering projections and transformations of X is equivalent to the category pro (π crs (X), Sets). We also prove that the latter category is equivalent...

Positive solutions of a renewal equation

Janusz Traple (1992)

Annales Polonici Mathematici

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An existence theorem is proved for the scalar convolution type integral equation x ( t ) = - h ( t - s ) f ( s , x ( s ) ) d s .