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Title

Commutative multiplication in three-dimensional space almost everywhere
Author

Alexander Kuleshov
Organization: Belarussian State University
Department: Chair of mathematical cybernetics
Description

It is known that finite-dimensional division algebras over \[DoubleStruckCapitalR] exist only in dimensions 1, 2, 4, 8. In this work the nontrivial example of commutative group in {(x,y,z)\[Element][\[DoubleStruckCapitalR]^3:x^2+y^2>0} will be constructed. Multiplication operation in this group is not co-ordinated with usual addition operation in \[DoubleStruckCapitalR]^3.

Operations of multiplication and division of vectors X, Y I define following formulas: X={x1,x2,x3}, Y={y1,y2,y3},

X⊗Y={(Sqrt[x1^2+x2^2+x3^2] (x1 y1-x2 y2) Sqrt[y1^2+y2^2+y3^2])/(x3 y3+Sqrt[x1^2+x2^2+x3^2] Sqrt[y1^2+y2^2+y3^2]),(Sqrt[x1^2+x2^2+x3^2] (x2 y1+x1 y2) Sqrt[y1^2+y2^2+y3^2])/(x3 y3+Sqrt[x1^2+x2^2+x3^2] Sqrt[y1^2+y2^2+y3^2]),(Sqrt[x1^2+x2^2+x3^2] Sqrt[y1^2+y2^2+y3^2] (Sqrt[x1^2+x2^2+x3^2] y3+x3 Sqrt[y1^2+y2^2+y3^2]))/(x3 y3+Sqrt[x1^2+x2^2+x3^2] Sqrt[y1^2+y2^2+y3^2])},

X/Y={(Sqrt[x1^2+x2^2+x3^2] (x1 y1+x2 y2))/(Sqrt[y1^2+y2^2+y3^2] (-x3 y3+Sqrt[x1^2+x2^2+x3^2] Sqrt[y1^2+y2^2+y3^2])),(Sqrt[x1^2+x2^2+x3^2] (x2 y1-x1 y2))/(Sqrt[y1^2+y2^2+y3^2] (-x3 y3+Sqrt[x1^2+x2^2+x3^2] Sqrt[y1^2+y2^2+y3^2])),(Sqrt[x1^2+x2^2+x3^2] (-Sqrt[x1^2+x2^2+x3^2] y3+x3 Sqrt[y1^2+y2^2+y3^2]))/(Sqrt[y1^2+y2^2+y3^2] (-x3 y3+Sqrt[x1^2+x2^2+x3^2] Sqrt[y1^2+y2^2+y3^2]))}.
Subjects

*Mathematics > Algebra
*Mathematics > Algebra > Group Theory
Keywords

Abelian group, three-dimensional arithmetical space
Language

Russian