Mathematics Problem Archive
Continuity of tuning in the host polynomial
v1.3 research notesAmong polynomials $P_1$ of degree greater than two with a superstable orbit of fixed period, does the tuning with a fixed $P_2$ vary continuously with...
Limit of tunings along growing periods
v1.3 research notesLet $P_{1,k}$ have a superstable orbit whose period tends to infinity and suppose $P_{1,k}\to P_{1,\infty}$. Do the tunings with a fixed polynomial $P...
Polynomial realization of intertwining
v1.3 research notesWhen does the topological intertwining construction for two polynomial dynamical planes yield a branched map conjugate to a polynomial?...
Quasiconformal construction of intertwinings
v1.3 research notesCan polynomial intertwinings be constructed by quasiconformal surgery?...
Continuity of polynomial intertwining
v1.3 research notesFor a fixed first polynomial $P_1$, does the polynomial obtained by intertwining $P_1$ with $P_2$ vary continuously with $P_2$?...
Non-equivalent compactifications of Blaschke-product space
v1.3 research notesFor a degree-$n$ Blaschke product $A$, let $B(A)$ be the rational maps obtained by mating $A$ with a varying Blaschke product, and let $F:B(z^n)\to B(...
Boundary quotient independent of base Blaschke product
v1.3 research notesQuotient the boundary of $B(A)$ by quasiconformal conjugacy, writing the quotient as $\partial(A)$. Prove that the natural isomorphism $F:B(z^n)\to B(...
Combinatorial boundary of Blaschke-product space
v1.3 research notesGive a combinatorial description, possibly by laminations, of the quotient boundary space $\partial(z^n)$ obtained from the boundary of $B(z^n)$ by id...
Domains of holomorphy for expanding-map components
v1.3 research notesIs $B(z^n)$ a domain of holomorphy? More generally, is every component of the space of expanding rational maps, or of expanding polynomials, a domain ...
Uniform geometry in complex renormalization
v1.3 research notesLet $f_i(z)=z^2+c_i$ range over finitely many critically periodic quadratic polynomials, let $g_n$ be the iterated tuning $f_1\vdash\cdots\vdash f_n$,...
Taylor-coefficient regularity of a Siegel conjugacy
v1.3 research notesFor $P_\rho'(z)=\lambda(1-z)^\rho$, $P_\rho(0)=0$, let $h$ linearize the Siegel disk and write $h'(\zeta)/(1-h(\zeta))=\sum_{\nu\ge0}a_\nu\zeta^\nu$. ...
Arc in a Cremer Julia set
v1.3 research notesFor $P_\alpha(z)=z^2+e^{2\pi i\alpha}z$ with a Cremer fixed point at $0$, is there an arc in its Julia set joining $0$ to its preimage $-e^{2\pi i\alp...
Topological model for a Cremer Julia set
v1.3 research notesGive a plausible topological model for the Julia set of a Cremer polynomial....
Lebesgue ergodicity on a spherical Julia set
v1.3 research notesIf $J(f)=\widehat{\mathbb C}$, is $f$ ergodic for Lebesgue measure? At least, does it have at most $2\deg f-2$ ergodic components?...
Accessibility of positive-exponent boundary points
v1.3 research notesIn the setting of Przytycki Problem 1.1, is every $x\in\partial U$ with $\liminf_{n\to\infty}n^{-1}\log|(f^n)'(x)|>0$ accessible from $U$?...
Unbounded Jacobian cocycles and singularity
v1.3 research notesFor which positive-entropy invariant measures $m$ does failure of uniform $L^2(m)$ boundedness of the sums of $\log\operatorname{Jac}_m f-\kappa\log|f...
Bounded Jacobian cocycles and absolute continuity
v1.3 research notesFor which positive-entropy invariant measures $m$ does uniform $L^2(m)$ boundedness of the sums of $\log\operatorname{Jac}_m f-\kappa\log|f'|$, where ...
Boundary theorems for geometric coding trees
v1.3 research notesWhich theorems about boundary behavior of Riemann maps have analogues for geometric coding trees?...
Representative transcendental entire dynamics
v1.3 research notesFind a collection of representative examples of transcendental entire maps whose dynamics may serve as models for general phenomena....
Newton dynamics for entire functions
v1.3 research notesDescribe the dynamics of Newton's method when applied to broad natural classes of transcendental entire functions....
An orbit converging to an irrationally indifferent fixed point
v1.3 research notesUnder the hypotheses of Eremenko–Lyubich Question 2, can even a single orbit converge to $z_0$?...
Degenerate-flow limits of bad Newton polynomials
v1.3 research notesCall a polynomial bad if its Newton map has an attracting cycle that is not a root. Prove that every bad degree-$d$ polynomial $f_1$ belongs to a one-...
Lift-family criterion for finite kneading data
v1.3 research notesFind a general property of a lifting family that guarantees convergence of the real Thurston algorithm for every periodic or preperiodic kneading sequ...
Lift-family criterion for arbitrary kneading data
v1.3 research notesFind a general property of a lifting family that guarantees convergence of the real Thurston algorithm for arbitrary kneading sequences....
Boundary fixed points in rank-zero Hénon components
v1.3 research notesIn the rank-zero case, if the limiting map on an invariant stable component is constant with value $x_0\in\partial U$, prove that one eigenvalue at $x...
Herman-ring retracts for Hénon maps
v1.3 research notesCan the subsequential limit map on an invariant stable component of a polynomial diffeomorphism of $\mathbb C^2$ be a retraction onto a Herman ring or...
Products involving Herman rings as stable components
v1.3 research notesIn the rank-two case for a polynomial diffeomorphism of $\mathbb C^2$, can an invariant stable component be a product of two Herman rings, or a produc...
Haken-type decomposition for rational maps
v1.3 research notesDevelop an analogue of the Haken decomposition for geometrically finite rational maps. In particular, if the Julia set is disconnected, can the map be...
Voronoi Diagram of Lines in 3D
v1.3 research notesWhat is the combinatorial complexity of the Voronoi diagram of a set of lines (or line segments) in three dimensions?...
Union of Fat Objects in 3D
v1.3 research notesWhat is the complexity of the union of ``fat'' objects in $\mathbb{R}^3$?...
$k$-sets
v1.3 research notesWhat is the maximum number of $k$-sets? (Equivalently, what is the maximum complexity of a $k$-level in an arrangement of hyperplanes?)...
Point Location in 3D Subdivision
v1.3 research notesIs there an $O(n)$-space data structure that supports $O(\log n)$-time point-location queries in a three-dimensional subdivision of $n$ faces?...
Vertical Decompositions in $\mathbb{R}^d$
v1.3 research notesWhat is the complexity of the vertical decomposition of $n$ surfaces in $\mathbb{R}^d$, $d \ge 5$?...
Minimum-Link Path in 2D
v1.3 research notesCan a minimum-link path among polygonal obstacles be found in subquadratic time?...
Polygonal Curve Simplification
v1.3 research notesCan an $n$-vertex polygonal curve be simplified in time nearly linear in $n$?...
Polyhedral Surface Approximation
v1.3 research notesHow efficiently can one compute a polyhedral surface that is an $\epsilon$-approximation of a given triangulated surface in $\mathbb{R}^3$?...
Flip Graph Connectivity in 3D
v1.3 research notesIs the flip graph connected for general-position points in $\mathbb{R}^3$? Given a set of $n$ points in $\mathbb{R}^3$, the flip graph has a node for ...
Hamiltonian Tetrahedralizations
v1.3 research notesCan every convex polytope in $\mathbb{R}^3$ be partitioned into tetrahedra such that the dual graph has a Hamiltonian path?...
Trapping Light Rays with Segment Mirrors
v1.3 research notesIs it possible to trap all the light from one point source by a finite collection of two-sided disjoint segment mirrors? A light ray is trapped if it ...
Extending Pseudosegment Arrangements by Subdivision
v1.3 research notesHow many intersections among an arrangement of pseudosegments in the plane must be added as vertices to allow the pseudosegment arrangment to be exten...
Counting Polyominoes
v1.3 research notesHow many polyominoes on $n$ squares are there? A polyomino is a connected interior-disjoint union of axis-aligned unit squares joined edge-to-edge, in...
Compatible Triangulations
v1.3 research notesIs it true that every two sets of $n$ planar points in general position with the same number points on their convex hulls have compatible triangulatio...
The Number of Pointed Pseudotriangulations
v1.3 research notesFor a planar point set $S$, is the number of pointed pseudotriangulations always at least the number of triangulations? A pseudotriangle is a planar p...
Vertex-Unfolding Polyhedra
v1.3 research notesConsider a polyhedron with simply connected facets (no holes on a facet) and without boundary (every edge is incident to exactly two facets). Can the ...
General Unfoldings of Nonconvex Polyhedra
v1.3 research notesCan every closed polyhedron be cut along its surface and unfolded into one piece in the plane without overlap? Such an unfolding is called a general u...
3D Minimum-Bend Orthogonal Graph Drawings
v1.3 research notesDoes every simple graph with maximum vertex degree $\Delta \leq 6$ have a 3D orthogonal point-drawing with no more than two bends per edge? A 3D ortho...
Planar Euclidean Maximum TSP
v1.3 research notesWhat is the complexity of finding a tour of maximum Euclidean length for a planar point set?...
Traveling Salesman Problem in Solid Grid Graphs
v1.3 research notesWhat is the complexity of finding a shortest tour in a solid planar grid graph? A planar grid graph is a graph whose vertices are any set of points on...
Pallet Loading
v1.3 research notesWhat is the complexity of the pallet loading problem? Given two pairs of numbers, $(A,B)$ and $(a,b)$, and a number $n$, decide whether $n$ small rect...
Most Circular Partition of a Square
v1.3 research notesWhat is the optimal partition of a square into convex pieces such that the circularity of the pieces is optimized? The circularity of a polygon is the...