Accola–Maclachlan bound
E904004
The Accola–Maclachlan bound is a refinement in algebraic geometry that gives an improved upper limit on the size of the automorphism group of a compact Riemann surface (or algebraic curve), sharpening the classical Hurwitz bound in certain cases.
Statements (40)
| Predicate | Object |
|---|---|
| instanceOf |
mathematical bound
ⓘ
result in algebraic geometry ⓘ result in the theory of Riemann surfaces ⓘ |
| appliesAlsoTo | smooth projective algebraic curves over algebraically closed fields of characteristic 0 ⓘ |
| appliesTo |
algebraic curves over the complex numbers
ⓘ
automorphism groups of compact Riemann surfaces ⓘ compact Riemann surfaces ⓘ |
| assumes |
compactness of the Riemann surface
ⓘ
genus at least 2 ⓘ |
| comparesWith | Hurwitz bound NERFINISHED ⓘ |
| concerns | relationship between genus of a Riemann surface and size of its automorphism group ⓘ |
| context |
finite group actions on Riemann surfaces
ⓘ
maximal automorphism groups of curves of given genus ⓘ |
| expresses | numerical constraint on |Aut(X)| in terms of the genus g of X ⓘ |
| field |
Riemann surface theory
NERFINISHED
ⓘ
algebraic geometry ⓘ automorphism groups of Riemann surfaces ⓘ complex analysis ⓘ group actions on Riemann surfaces ⓘ |
| gives | upper bound on the order of the automorphism group of a compact Riemann surface ⓘ |
| goal | sharpen the general upper bound on automorphism groups beyond Hurwitz’s 84(g−1) bound in special cases ⓘ |
| hasDomain | compact Riemann surfaces of genus g ≥ 2 ⓘ |
| historicalContext | 20th century developments in the theory of Riemann surfaces ⓘ |
| improvesOn | classical Hurwitz bound in certain genera ⓘ |
| involves |
finite groups of conformal automorphisms
ⓘ
hyperbolic geometry of Riemann surfaces ⓘ |
| language |
algebro-geometric formulation
ⓘ
complex analytic formulation ⓘ |
| mathematicalObject | inequality relating genus and automorphism group order ⓘ |
| namedAfter |
Colin Maclachlan
NERFINISHED
ⓘ
Robert D. M. Accola NERFINISHED ⓘ |
| refines | Hurwitz bound NERFINISHED ⓘ |
| relatedTo |
Fuchsian groups
ⓘ
Hurwitz surfaces NERFINISHED ⓘ automorphism groups of algebraic curves ⓘ uniformization of Riemann surfaces ⓘ |
| typeOf |
group-theoretic bound in geometry
ⓘ
inequality in complex geometry ⓘ |
| usedFor |
classifying Riemann surfaces with large automorphism groups
ⓘ
studying extremal Riemann surfaces with many automorphisms ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.