Organizing Committee

Thurston maps are orientation-preserving branched covering maps of the two-sphere to itself for which the forward orbits of the branch points form a finite set. They arise in the classification of complex dynamical systems.

Recent work has shown close connections between the combinatorial, topological, and algebraic theory of Thurston maps and that of mapping class groups. The algorithmic and computational theories of mapping class groups are highly advanced and have reached the point of effective implementation via computer programs. However, such implementations for Thurston maps are significantly less advanced. The aim of the proposed Hot Topic workshop is to bring together researchers in the computational theory of mapping class groups and those in the combinatorial theory of Thurston maps in order to make headway on fundamental problems.

Confirmed Speakers & Participants

  • Speaker
  • Poster Presenter
  • Attendee

Workshop Schedule

Saturday, November 2, 2019
8:30 - 8:55Registration11th Floor Registration Desk 
8:55 - 9:00Welcome - ICERM Director11th Floor lecture Hall 
9:00 - 9:45Mapping Class Group Algorithms - Johanna Mangahas, University of Buffalo11th Floor Lecture Hall
10:00 - 10:30Coffee/Tea Break11th Floor Collaborative Space 
10:30 - 11:15TBA - Rebecca Winarski, University of Michigan11th Floor Lecture Hall 
11:30 - 12:15Fast Nielsen-Thurston Classification - Öykü Yurttas, Dicle University11th Floor Lecture Hall
12:30 - 1:45Break for Lunch/Free Time  
1:45 - 2:45TBA - James Belk, University of St Andrews11th Floor Lecture Hall 
2:45 - 3:45Complexity of Thurston Decidability - Dzmitry Dudko, Stony Brook University11th Floor Lecture Hall
3:45 - 4:15Coffee/Tea Break11th Floor Collaborative Space 
4:30 - 5:00Lighting Talks and Software Demo - TBA11th Floor Lecture Hall 
5:00 - 7:00Welcome Reception11th Floor Collaborative Space 
Sunday, November 3, 2019
9:00 - 9:45TBA - Saul Schleimer, University of Warwick11th Floor Lecture Hall 
10:00 - 10:10Group Photo11th Floor Lecture Hall 
10:10 - 10:30Coffee/Tea Break11th Floor Collaborative Space 
10:30 - 11:15Dynamical Mapping Classess Associated to a Rational Map - Sarah Koch, University of Michigan11th Floor Lecture Hall
11:30 - 12:15Deformation Spaces of Rational Maps - Tanya Firsova, Kansas State University11th Floor Lecute Hall
12:30 - 2:00Break for Lunch/Free Time  
2:00 - 2:45A Skew Product Map with a Non-Contracting Iterated Monodromy Group - Volodymyr Nekrashevych, Texas A&M University11th Floor Lecture Hall
3:00 - 3:45Elastic Graphs - Dylan Thurston, Indiana University11th Floor Lecture Hall
4:00 - 4:30Coffee/Tea Break11th Floor Collaborative Space 

Application Information

ICERM welcomes applications from faculty, postdocs, graduate students, industry scientists, and other researchers who wish to participate. Some funding may be available for travel and lodging. Graduate students who apply must have their advisor submit a statement of support in order to be considered.

Your Visit to ICERM

ICERM Facilities
ICERM is located on the 10th & 11th floors of 121 South Main Street in Providence, Rhode Island. ICERM's business hours are 8:30am - 5:00pm during this event. See our facilities page for more info about ICERM and Brown's available facilities.
Traveling to ICERM
ICERM is located at Brown University in Providence, Rhode Island. Providence's T.F. Green Airport (15 minutes south) and Boston's Logan Airport (1 hour north) are the closest airports. Providence is also on Amtrak's Northeast Corridor. In-depth directions and transportation information are available on our travel page.
To secure ICERM's preferred hotel rate at the Hampton Inn & Suites Providence Downtown, use this link. ICERM regularly works with two additional area hotels for short visits. The Graduate Hotel and Hilton Garden Inn both have discounted rates available. Contact before booking outside of the preferred rate or if you would like to book alternate accommodations.
The only way ICERM participants should book a room is through the hotel reservation links located on this page or through links emailed to them from an ICERM email address ( ICERM never works with any conference booking vendors and never collects credit card information.
Those traveling with family who are interested in information about childcare and/or schools should contact
Technology Resources
Wireless internet access ("Brown-Guest") and wireless printing is available for all ICERM visitors. Eduroam is available for members of participating institutions. Thin clients in all offices and common areas provide open access to a web browser, SSH terminal, and printing capability. See our Technology Resources page for setup instructions and to learn about all available technology.
Discrimination and Harassment Policy
ICERM is committed to creating a safe, professional, and welcoming environment that benefits from the diversity and experiences of all its participants. Both the Brown University "Code of Conduct" and the "Discrimination and Workplace Harassment Policy" apply to all ICERM participants and staff. Participants with concerns or requests for assistance on a discrimination or harassment issue should contact the ICERM Director, who is the responsible employee at ICERM under this policy.
Exploring Providence
Providence's world-renowned culinary scene provides ample options for lunch and dinner. Neighborhoods near campus, including College Hill Historic District, have many local attractions. Check out the map on our Explore Providence page to see what's near ICERM.

Visa Information

Contact for assistance.

Eligible to be reimbursed
B-1 or Visa Waiver Business (WB)
Ineligible to be reimbursed
B-2 or Visa Waiver Tourist (WT)
Already in the US?

F-1 and J-1 not sponsored by ICERM: need to obtain a letter approving reimbursement from the International Office of your home institution PRIOR to travel.

H-1B holders do not need letter of approval.

All other visas: alert ICERM staff immediately about your situation.

ICERM does not reimburse visa fees. This chart is to inform visitors whether the visa they enter the US on allows them to receive reimbursement for the items outlined in their invitation letter.

Financial Support

Acceptable Costs
  • 1 roundtrip between your home institute and ICERM
  • Flights in economy class to either Providence airport (PVD) or Boston airport (BOS)
  • Ground Transportation to and from airports and ICERM.
Unacceptable Costs
  • Seats in economy plus, business class, or first class
  • Change ticket fees of any kind
  • Multi-use bus passes
  • Meals or incidentals
Advance Approval Required
  • Personal car travel to ICERM from outside New England
  • Multiple-destination plane ticket; does not include layovers to reach ICERM
  • Arriving or departing from ICERM more than a day before or day after the program
  • Multiple trips to ICERM
  • Rental car to/from ICERM
  • Arriving or departing from airport other than PVD/BOS or home institution's local airport
  • 2 one-way plane tickets to create a roundtrip (often purchased from Expedia, Orbitz, etc.)
Reimbursement Request Form

Refer to the back of your ID badge for more information. Checklists are available at the front desk.

Reimbursement Tips
  • Scanned original receipts are required for all expenses
  • Airfare receipt must show full itinerary and payment
  • ICERM does not offer per diem or meal reimbursement
  • Allowable mileage is reimbursed at prevailing IRS Business Rate and trip documented via pdf of Google Maps result
  • Keep all documentation until you receive your reimbursement!
Reimbursement Timing

6 - 8 weeks after all documentation is sent to ICERM. All reimbursement requests are reviewed by numerous central offices at Brown who may request additional documentation.

Reimbursement Deadline

Submissions must be received within 30 days of ICERM departure to avoid applicable taxes. Submissions after thirty days will incur applicable taxes. No submissions are accepted more than six months after the program end.