On a theorem of Baer, Schreier, and Ulam for permutations
نویسندگان
چکیده
منابع مشابه
Digital Borsuk-Ulam theorem
The aim of this paper is to compute a simplicial cohomology group of some specific digital images. Then we define ringand algebra structures of a digital cohomology with the cup product. Finally, we prove a special case of the Borsuk-Ulam theorem fordigital images.
متن کاملThe Artin-schreier Theorem
The algebraic closure of R is C, which is a finite extension. Are there other fields which are not algebraically closed but have an algebraic closure which is a finite extension? Yes. An example is the field of real algebraic numbers. Since complex conjugation is a field automorphism fixing Q, and the real and imaginary parts of a complex number can be computed using field operations and comple...
متن کاملA Borsuk-Ulam theorem for digital images
The Borsuk-Ulam theorem states that a continuous function f : S → R has a point x ∈ S with f(x) = f(−x). We give an analogue of this theorem for digital images, which are modeled as discrete spaces of adjacent pixels equipped with Z-valued functions. In particular, for a concrete two-dimensional rectangular digital image whose pixels all have an assigned “brightness” function, we prove that the...
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ژورنال
عنوان ژورنال: Journal of Algebra
سال: 1979
ISSN: 0021-8693
DOI: 10.1016/0021-8693(79)90161-3