Symmetric Riemann surfaces with no points fixed by orientation preserving automorphisms

2020 ◽  
Vol 126 (3) ◽  
pp. 479-492
Author(s):  
Ewa Kozłowska-Walania
Keyword(s):  
Finite Group ◽  
Fixed Points ◽  
Upper Bound ◽  
Riemann Surfaces ◽  
Dihedral Groups ◽  
Minimal Genus

We study the symmetric Riemann surfaces for which the group of orientation preserving automorphisms acts without fixed points. We show that any finite group can give rise to such an action, determine the maximal number of non-conjugate symmetries for such surfaces and find a sharp upper bound on maximal total number of ovals for a set of $k$ symmetries with ovals. We also solve the minimal genus problem for dihedral groups acting on the surfaces described above, for odd genera.

ALTERNATING GROUPS AS AUTOMORPHISM GROUPS OF RIEMANN SURFACES

2006 ◽  
Vol 16 (01) ◽  
pp. 91-98
Author(s):  
J. J. ETAYO GORDEJUELA ◽  
E. MARTÍNEZ
Keyword(s):  
Riemann Surface ◽  
Automorphism Group ◽  
Upper Bound ◽  
Riemann Surfaces ◽  
Automorphism Groups ◽  
Alternating Groups ◽  
Minimal Genus

In this work we give pairs of generators (x, y) for the alternating groups An, 5 ≤ n ≤ 19, such that they determine the minimal genus of a Riemann surface on which An acts as the automorphism group. Using these results we prove that A15 is the unique of these groups that is an H*-group, i.e., the groups achieving the upper bound of the order of an automorphism group acting on non-orientable unbordered surfaces.

scholarly journals ON FIXED POINTS OF DOUBLY SYMMETRIC RIEMANN SURFACES

2008 ◽  
Vol 50 (3) ◽  
pp. 371-378 ◽  
Author(s):  
GRZEGORZ GROMADZKI ◽  
EWA KOZŁOWSKA-WALANIA
Keyword(s):  
Fixed Points ◽  
Upper Bound ◽  
Riemann Surfaces ◽  
Upper Bounds

AbstractIn this paper, we study ovals of symmetries and the fixed points of their products on Riemann surfaces of genus g ≥ 2. We show how the number of these points affects the total number of ovals of symmetries. We give a generalisation of Bujalance, Costa and Singerman's theorems in which we show upper bounds for the total number of ovals of two symmetries in terms of g, the order n and the number m of the fixed points of their product, and we show their attainments for n holding some divisibility conditions. Finally, we give an upper bound for m in terms of n and g, and we study conditions under which it has given parity.

The Laitinen Conjecture for finite non-solvable groups

2012 ◽  
Vol 56 (1) ◽  
pp. 303-336 ◽  
Author(s):  
Krzysztof Pawałowski ◽  
Toshio Sumi
Keyword(s):  
Finite Group ◽  
Fixed Points ◽  
Solvable Group ◽  
Prime Power ◽  
Solvable Groups ◽  
Conjugacy Classes ◽  
Prime Power Order ◽  
Algebraic Condition ◽  
Smooth Action

AbstractFor any finite group G, we impose an algebraic condition, the Gnil-coset condition, and prove that any finite Oliver group G satisfying the Gnil-coset condition has a smooth action on some sphere with isolated fixed points at which the tangent G-modules are not isomorphic to each other. Moreover, we prove that, for any finite non-solvable group G not isomorphic to Aut(A6) or PΣL(2, 27), the Gnil-coset condition holds if and only if rG ≥ 2, where rG is the number of real conjugacy classes of elements of G not of prime power order. As a conclusion, the Laitinen Conjecture holds for any finite non-solvable group not isomorphic to Aut(A6).

Fixed Points of Automorphisms of Compact Riemann Surfaces

1970 ◽  
Vol 22 (5) ◽  
pp. 922-932 ◽  
Author(s):  
M. J. Moore
Keyword(s):  
Fixed Point ◽  
Fixed Points ◽  
Riemann Surfaces ◽  
Homology Group ◽  
Group Of Automorphisms ◽  
Quartic Curve ◽  
Lefschetz Fixed Point Formula ◽  
Compact Riemann Surfaces ◽  
Klein's Quartic Curve ◽  
Fundamental Paper

In his fundamental paper [3], Hurwitz showed that the order of a group of biholomorphic transformations of a compact Riemann surface S into itself is bounded above by 84(g – 1) when S has genus g ≧ 2. This bound on the group of automorphisms (as we shall call the biholomorphic self-transformations) is attained for Klein's quartic curve of genus 3 [4] and, from this, Macbeath [7] deduced that the Hurwitz bound is attained for infinitely many values of g.After genus 3, the next smallest genus for which the bound is attained is the case g = 7. The equations of such a curve of genus 7 were determined by Macbeath [8] who also gave the equations of the transformations. The equations of these transformations were found by using the Lefschetz fixed point formula. If the number of fixed points of each element of a group of automorphisms is known, then the Lefschetz fixed point formula may be applied to deduce the character of the representation given by the group acting on the first homology group of the surface.

scholarly journals Commutator Length of Finitely Generated Linear Groups

2008 ◽  
Vol 2008 ◽  
pp. 1-5
Author(s):  
Mahboubeh Alizadeh Sanati
Keyword(s):  
Finite Group ◽  
Upper Bound ◽  
Quadratic Polynomial ◽  
Linear Groups ◽  
Number Of Generators ◽  
Derived Subgroup ◽  
Finite Linear Group ◽  
Minimum Number ◽  
Commutator Length ◽  
Finite Linear

The commutator length “” of a group is the least natural number such that every element of the derived subgroup of is a product of commutators. We give an upper bound for when is a -generator nilpotent-by-abelian-by-finite group. Then, we give an upper bound for the commutator length of a soluble-by-finite linear group over that depends only on and the degree of linearity. For such a group , we prove that is less than , where is the minimum number of generators of (upper) triangular subgroup of and is a quadratic polynomial in . Finally we show that if is a soluble-by-finite group of Prüffer rank then , where is a quadratic polynomial in .

scholarly journals Mixed threefolds isogenous to a product

2019 ◽  
Vol 18 (12) ◽  
pp. 1950239 ◽  
Author(s):  
Christian Gleissner
Keyword(s):  
Finite Group ◽  
Riemann Surfaces ◽  
Mixed Type ◽  
General Type ◽  
Canonical Class ◽  
Trivial Element ◽  
Compact Riemann Surfaces ◽  
A Finite Group ◽  
Full Classification

In this paper, we study threefolds isogenous to a product of mixed type i.e. quotients of a product of three compact Riemann surfaces [Formula: see text] of genus at least two by the action of a finite group [Formula: see text], which is free, but not diagonal. In particular, we are interested in the systematic construction and classification of these varieties. Our main result is the full classification of threefolds isogenous to a product of mixed type with [Formula: see text] in the absolutely faithful case, i.e. any automorphism in [Formula: see text], which restricts to the trivial element in [Formula: see text] for some [Formula: see text], is the identity on the product. Since the holomorphic Euler–Poincaré-characteristic of a smooth threefold of general type with ample canonical class is always negative, these examples lie on the boundary, in the sense of threefold geography. To achieve our result we use techniques from computational group theory. Indeed, we develop a MAGMA algorithm to classify these threefolds for any given value of [Formula: see text] in the absolutely faithful case.

scholarly journals Fixed Points on Asymmetric Riemann Surfaces

2020 ◽  
Vol 17 (4) ◽  
Author(s):  
Ewa Kozłowska-Walania ◽  
Ewa Tyszkowska
Keyword(s):  
Fixed Points ◽  
Riemann Surfaces

scholarly journals On groups admitting a noncyclic abelian automorphism group

1973 ◽  
Vol 9 (3) ◽  
pp. 363-366 ◽  
Author(s):  
J.N. Ward
Keyword(s):  
Fixed Point ◽  
Finite Group ◽  
Automorphism Group ◽  
Fixed Points ◽  
Free Operator ◽  
A Finite Group

It is shown that a condition of Kurzwell concerning fixed-points of certain operators on a finite group G is sufficient to ensure that G is soluble. The result generalizes those of Martineau on elementary abelian fixed-point-free operator groups.

Sign in / Sign up

Export Citation Format

Share Document