TY - JOUR
T1 - Maps with No a Priori Bounds
AU - Blokh, Alexander
AU - Levin, Genadi
AU - Oversteegen, Lex
AU - Timorin, Vladlen
N1 - Publisher Copyright:
© The Author(s) 2025.
PY - 2025/6
Y1 - 2025/6
N2 - The modulus of a polynomial-like (PL) map is an important invariant that controls distortion of the straightening map and, hence, geometry of the corresponding PL Julia set. Lower bounds on the modulus, called complex a priori bounds, are known in a great variety of contexts. For any rational function we complement this by an upper bound for moduli of PL maps in the satellite case that depends only on the relative period and the degree of the PL map. This rules out a priori bounds in the satellite case with unbounded relative periods. We also apply our tools to obtain lower bounds for hyperbolic lengths of geodesics in the infinitely renormalizable case, and to show that moduli of annuli must converge to 0 for a sequence of arbitrary renormalizations, under several conditions all of which are shown to be necessary.
AB - The modulus of a polynomial-like (PL) map is an important invariant that controls distortion of the straightening map and, hence, geometry of the corresponding PL Julia set. Lower bounds on the modulus, called complex a priori bounds, are known in a great variety of contexts. For any rational function we complement this by an upper bound for moduli of PL maps in the satellite case that depends only on the relative period and the degree of the PL map. This rules out a priori bounds in the satellite case with unbounded relative periods. We also apply our tools to obtain lower bounds for hyperbolic lengths of geodesics in the infinitely renormalizable case, and to show that moduli of annuli must converge to 0 for a sequence of arbitrary renormalizations, under several conditions all of which are shown to be necessary.
UR - http://www.scopus.com/inward/record.url?scp=105006816836&partnerID=8YFLogxK
U2 - 10.1007/s00220-025-05303-8
DO - 10.1007/s00220-025-05303-8
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AN - SCOPUS:105006816836
SN - 0010-3616
VL - 406
JO - Communications in Mathematical Physics
JF - Communications in Mathematical Physics
IS - 6
M1 - 141
ER -