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Theoretical Computer Science, Cybernetics
Violation of finite approximability for single-coefficient commutant equations
V. G. Durneva, A. I. Zetkinaab a P.G. Demidov Yaroslavl State University, Yaroslavl
b Voronezh State University, Voronezh
Abstract:
We construct an equation (resolved with respect to unknowns) such that (i) it has no solution in $F_2$ (a free group of rank $2$), but (ii) it has a solution in any finite homomorphic image of $F_2$. The left-hand-side of this equation belongs to the derived subgroup (i.e. has zero sum of exponents in each variable), while its right-hand-side is the commutator of two generators of $F_2$.
Keywords:
free group, equation in a free group, residual finiteness, commutator of elements, commutator subgroup.
Received: 21.04.2022 Revised: 18.05.2022
Citation:
V. G. Durnev, A. I. Zetkina, “Violation of finite approximability for single-coefficient commutant equations”, Vestnik TVGU. Ser. Prikl. Matem. [Herald of Tver State University. Ser. Appl. Math.], 2022, no. 2, 5–13
Linking options:
https://www.mathnet.ru/eng/vtpmk633 https://www.mathnet.ru/eng/vtpmk/y2022/i2/p5
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| Abstract page: | 279 | | Full-text PDF : | 141 | | References: | 73 |
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