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Finite index subgroups of fully . . .
, 2008
"... Using graphtheoretic techniques for f.g. subgroups of F Z[t] we provide a criterion for a f.g. subgroup of a f.g. fully residually free group to be of finite index. Moreover, we show that this criterion can be checked effectively. Also we obtain an analogue of GreenbergStallings Theorem for f.g. f ..."
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Using graphtheoretic techniques for f.g. subgroups of F Z[t] we provide a criterion for a f.g. subgroup of a f.g. fully residually free group to be of finite index. Moreover, we show that this criterion can be checked effectively. Also we obtain an analogue of GreenbergStallings Theorem for f
Homology in Finite Index Subgroups
, 2009
"... This thesis looks at the following question: If G is a finitely presented group and ..."
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This thesis looks at the following question: If G is a finitely presented group and
ON FINITE INDEX SUBGROUPS OF A UNIVERSAL GROUP
"... Abstract. The orbifold group of the Borromean rings with singular angle 90 degrees, U, is a universal group, because every closed oriented 3–manifold M 3 occurs as a quotient space M 3 = H 3 /G, where G is a finite index subgroup of U. Therefore, an interesting, but quite difficult problem, is to cl ..."
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Abstract. The orbifold group of the Borromean rings with singular angle 90 degrees, U, is a universal group, because every closed oriented 3–manifold M 3 occurs as a quotient space M 3 = H 3 /G, where G is a finite index subgroup of U. Therefore, an interesting, but quite difficult problem
Finite index subgroups of the modular group and their modular forms
, 2007
"... Abstract. Classically, congruence subgroups of the modular group, which can be described by congruence relations, play important roles in group theory and modular forms. In reality, the majority of finite index subgroups of the modular group are noncongruence. These groups as well as their modular f ..."
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Cited by 7 (1 self)
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Abstract. Classically, congruence subgroups of the modular group, which can be described by congruence relations, play important roles in group theory and modular forms. In reality, the majority of finite index subgroups of the modular group are noncongruence. These groups as well as their modular
Classification and statistics of finite index subgroups in free products
 Adv. Math
"... For positive integers e and m denote by C∗em the free product of e copies of the cyclic group of order m, and let Fr be the free group of rank r. Given integers r, t ≥ 0, distinct primes p1,..., pt, and positive integers e1,..., et, let Γ = C∗e1p1 ∗ · · · ∗ C∗etpt ∗ Fr. (1) By the Kurosh subgrou ..."
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Cited by 2 (2 self)
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subgroup theorem, a finite index subgroup ∆ ≤ Γ is again of the same form, that is, ∆ ∼ = C∗λ1p1 ∗ · · · ∗ C∗λtpt ∗ Fµ with nonnegative integers λ1,..., λt, µ. An Euler characteristic computation shows that the latter parameters are related to the index (Γ: ∆) via the relation∑ j λj
Finite index subgroups of R. Thompson’s group F. preprint
"... ABSTACT: The authors classify the finite index subgroups of R. Thompson’s group F. All such groups that are not isomorphic to F are nonsplit extensions of finite cyclic groups by F. The classification describes precisely which finite index subgroups of F are isomorphic to F, and also separates the ..."
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Cited by 1 (0 self)
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ABSTACT: The authors classify the finite index subgroups of R. Thompson’s group F. All such groups that are not isomorphic to F are nonsplit extensions of finite cyclic groups by F. The classification describes precisely which finite index subgroups of F are isomorphic to F, and also separates
Curve complexes and finite index subgroups of mapping class groups
"... Abstract. Let Mod(S) be the extended mapping class group of a surface S. For S the twicepunctured torus, we show that there exists an isomorphism of finite index subgroups of Mod(S) which is not the restriction of an inner automorphism. For S a torus with at least three punctures or a genus two sur ..."
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Cited by 26 (4 self)
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Abstract. Let Mod(S) be the extended mapping class group of a surface S. For S the twicepunctured torus, we show that there exists an isomorphism of finite index subgroups of Mod(S) which is not the restriction of an inner automorphism. For S a torus with at least three punctures or a genus two
Finiteindex subgroups and images of profinite groups
"... This mini course will study profinite groups from asymptotic properties of their finite images. I will indicate a proof that every finite image of a finitely generated profinite group G is continuous and hence the topology of G can be recovered from the group structure. Some applications and open pr ..."
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This mini course will study profinite groups from asymptotic properties of their finite images. I will indicate a proof that every finite image of a finitely generated profinite group G is continuous and hence the topology of G can be recovered from the group structure. Some applications and open
Results 1  10
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10,882