Commit 2020-12-07 10:37 44400c99
View on Github →feat(dynamics/circle/rotation_number): translation numbers define a group action up to a semiconjugacy (#5138)
Formalize a theorem by Étienne Ghys: given two lifts f₁
, f₂
of
actions of a group G
on the circle by orientation preserving
homeomorphisms to the real line, assume that for each g : G
the
translation numbers of f₁ g
and f₂ g
are equal. Then the actions
are semiconjugate by a (possibly discontinuous) circle map.