## Dr. Philipp Hieronymi

Associate Professor

#### News | Teaching | Research

### Contact Information

Office: Room 332, Illini Hall

E-mail: phierony@illinois.edu

Phone: 217-300-4994

Mailing Address:

Department of Mathematics

University of Illinois at Urbana-Champaign

1409 W. Green Street (MC-382)

Urbana, IL 61801

I am the faculty advisor of the
Pi Mu Epsilon Illinois Alpha Chapter.

I am a mentor for MathAlliance.

If you are a former or current student, please connect with me on LinkedIn.

### News

## Math 415 - Fall 2017If you are a student trying to enroll in any of the Math 415 sections for the Fall semester 2017, please contact the undergraduate math advisers by stopping by 313 Altgeld Hall (business days between 8:30-noon or 1-4:30 pm) or sending an e-mail to mathadvising@illinois.edu.If you are enrolled in Math 415, you can access the Learn@Illinios course website under https://learn.illinois.edu/course/view.php?id=24050. Please note that if you have just registered for the course, it might take 48 hours for you to get access to the Learn@Illinois website. | |

## A Math Carnival at IllinoisHundreds of local adults and children converged on Altgeld Hall on Saturday, January 28th 2017 for Math Carnival: Gathering for Gardner. As they participated in the numerous puzzles, games, riddles, magic tricks, and other hands-on activities, they discovered that math is more than just figures and formulas. According to Melinda Lanius, a math Ph.D. student who, along with Assistant Professor Philipp Hieronymi, organized this year’s event, “Math is play!” So numerous volunteers from Illinois’ Department of Mathematics, Illinois Geometry Lab, and Association for Women in Mathematics spent the afternoon showing members of the community that play can indeed be math—and that it’s fun. For more details, see the ISTEM report. |

More news...

### Research

My research in logic focuses on ordered structures and their potential applications in analysis and geometry.

My research has been partially supported by NSF grant DMS-1300402 and DMS-1654725. More details...

### Publications

- 'Defining the set of integers in expansions of the real field by a closed discrete set',

*Proc. Amer. Math. Soc.*138 (2010) 2163-2168, arXiv:0906.4972 - 'The real field with the rational points of an elliptic curve', with Ayhan Günaydin,
*Fund. Math.*211 (2011) 15-40, arXiv:0906.0528 - 'Dependent pairs', with Ayhan Günaydin,
*J. Symb. Logic*(2) 76 (2011) 377-390, arXiv:1003.5025 - 'The real field with an irrational power function and a dense multiplicative subgroup',

*J. London Math. Soc.*(2) 83 (2011) 153-167, doi: 10.1112/jlms/jdq058, - 'Expansions of subfields of the real field by a discrete set',
*Fund. Math.*215 (2011) 167-175, arXiv:1012.3508 - 'Expansions which introduce no new open sets', with Gareth Boxall,

*J. Symb. Logic*(1) 77 (2012) 111-121, arXiv:1002.3762 - 'A dichotomy for expansions of the real field', with Antongiulio Fornasiero and Chris Miller,

*Proc. Amer. Math. Soc.*141 (2013) 697-698, arXiv:1105.2946 - 'An analogue of the Baire Category Theorem',
*J. Symb. Logic*(1) 78 (2013) 207-213, arXiv:1101.1194 - 'Interpreting the projective hierarchy in expansions of the real line', with Michael Tychonievich,

*Proc. Amer. Math. Soc.*142 (2014) 3259-3267, pdf - 'A fundamental dichotomy for definably complete expansions of
ordered fields', with Antongiulio Fornasiero,
*J. Symb. Logic*(4) 80 (2015) 1091-1115 pdf - 'Expansions of the ordered additive group of real numbers by two discrete subgroups',
*J. Symb. Logic*(3) 81 (2016) 1007–1027 pdf - 'Distal and non-distal pairs', with Travis Nell,

*J. Symb. Logic*(1) 82 (2017) 375-383 pdf - 'How to avoid a compact set' with Antongiulio Fornasiero and Erik Walsberg,

*Adv. Math.*317 (2017) 758-785 pdf - 'Ostrowski numeration systems, addition and finite automata', with Alonza Terry Jr,
*Notre Dame J. Formal Logic*to appear pdf - 'A tame Cantor set',

*J. European Math. Soc.*to appear pdf - 'Interpreting the monadic second order theory of one successor in expansions of the real line', with Erik Walsberg,

*Israel J. Math.*to appear pdf - 'Wild theories with o-minimal open core' with Travis Nell and Erik Walsberg,

*Ann. Pure Appl. Logic*to appear pdf - DPhil Thesis, 'The real field with an irrational power function and a dense multiplicative subgroup',

ORA, Nov. 2008

Preprints

- 'When is scalar multiplication decidable?', pdf
- 'Metric dimensions and tameness in expansions of the real field' with Chris Miller, pdf
- 'Structure theorems in tame expansions of o-minimal structures by a dense set' with Pantelis Eleftheriou and Ayhan Günaydin, pdf
- 'Definability and decidability in expansions by generalized Cantor sets' with William Balderrama, pdf
- 'The Choice Property in tame expansions of o-minimal structures' with Pantelis Eleftheriou and Ayhan Günaydin, pdf
- 'On continuous functions definable in expansions of the ordered real additive group' with Erik Walsberg, pdf

Work by students

- 'On expansions of the real field by complex subgroups', by Erin Caulfield,
*Ann. Pure Appl. Logic*168 (2017) 1308–1334 pdf

Economics

- 'The Clean-Development Mechanism, stochastic permit prices and energy investments' with David Schüller,

*Energy Economics*47 (2015) 25–36 - 'The Influence of Permit Price Uncertainty and Lobbying on Energy Investments' with David Schüller,

in 'Emissions Trading as a Policy Instrument: Evaluation and Prospects',*CESifo Seminar Series, MIT Press*(2015) 87-120

### Advising

Postdocs- Erik Walsberg, since 2016

- Erin Caulfield, since 2013, passed Prelim December 2014
- Travis Nell, since 2014, passed Prelim August 2015

- Pete Glaze (2010-2011)
- Nathan Rehfuss (2013-2014)
- Alonza Terry Jr. (2013-2016)
- William Balderrama (2016)
- Alexi Block Gorman (since 2017)

### Teaching

Fall 2016 - Math 415 - Applied Linear Algebra

Fall 2015 - Math 415 - Applied Linear Algebra

Fall 2014 - Math 415 - Applied Linear Algebra

Spring 2014 - Math 415 - Applied Linear Algebra

Fall 2013 - Math 415 - Applied Linear Algebra

Fall 2013 - Math 595 - O-minimal structures

Spring 2013 - Math 414 - Mathematical Logic

Fall 2012 - Math 570 - Mathematical Logic

Spring 2012 - Math 225 - Section P1 - Intro Matrix Theory

Spring 2012 - Math 414 - Mathematical Logic

Fall 2011 - Math 347 - Section G1 - Fundamental Mathematics

Spring 2011 - Math 225 - Section P1 - Intro Matrix Theory

Spring 2011 - Math 414 - Mathematical Logic

Fall 2010 - Math 285 - Section L1 - Intro Differential Equations

### Vita

- DPhil, University of Oxford, 2008,
- DAAD Postdoctoral Fellow at McMaster University and the Fields Institute, 2009,
- J.L. Doob RAP at the University of Illinois at Urbana-Champaign, January 2010 - May 2012
- Assistant Professor at the University of Illinois at Urbana-Champaign, since August 2012

### Old News

## A Math Carnival at IllinoisYou love mathematics? Fantastic! You don't like mathematics? Well, then give us a chance to change that! The Department of Mathematics at the University of Illinois at Urbana-Champaign would like to invite you and your family to our winter math carnival! The Gathering for Gardner 2017 will be held on Saturday, January 28, 2017 from 2 - 5 pm in Altgeld Hall. This fun filled day will be packed with hands on activities, demonstrations, games and puzzles, refreshments, and mathematical prizes for participants! All activities are free and open to the public and there is no math training required to enjoy! Our puzzles are particularly designed for kindergarten, elementary school, and middle school students. Please come visit us and bring the whole family!For more details, see https://faculty.math.illinois.edu/~lanius2/G4G.html or join us on Facebook. | |

## PME is seeking application for membershipThe local chapter of Pi Mu Epsilon (PME) is seeking application for membership. PME is the National Mathematics Honorary Society that serves to promote scholarly activity in mathematics among the students in academic institutions. To be elected as a member to the Illinois Alpha Chapter of Pi Mu Epsilon, an undergraduate student at the University of Illinois at Urbana-Champaign has to meet all of the following requirements:(i) Completion of the calculus sequence through MATH 241 or the equivalent (ii) Completion of at least two post-calculus courses that count toward a major in the mathematical sciences (e.g. any two of MATH 210, 347, 408 and 461) (iii) a 3.5 or higher math GPA (iv) a 3.2 or higher U of I GPA. We are accepting applications from now until Friday, March 4, 2016. The membership form may be acquired from the Undergraduate Math Office in 313 Altgeld Hall or downloaded here. If you have any questions, please contact Professor Philipp Hieronymi (phierony@illinois.edu) or Math Advising (mathadvising@illinois.edu).
| |

## Enrollment - Math 415 - Fall 2015If you are a student trying to enroll in one of my Math 415 sections, please note that enrollment is not handled by me, but by the undergraduate math advisers. You can contact them by stopping by 313 Altgeld Hall (business days between 8:30-noon or 1-4:30 pm) or send an e-mail to mathadvising@illinois.edu. | |

## Impressions from the Gathering for Gardner 2014At the occasion of Gardner's 100th birthday the Illinois Geometry Lab and Department of Mathematics at the University of Illinois at Urbana-Champaign hosted a celebration of recreational mathematics and fun math puzzles on Saturday October 11th of this year. This event, a Gathering for Gardner 2014, was to honor the achievements of popular mathematics writer Martin Gardner who, for over 50 years, entertained general audiences with a rich variety of mathematical puzzles. Local mathematicians and computer scientists provided demonstrations of magic tricks, visual paradoxes and much more! At our math fair children of all ages (and adults as well!) were able to attempt and solve a large variety of Gardner's puzzles. For pictures of the event, click here. For more information about the event, click here. | |

## Gathering for Gardner 2014 - Oct 11, 1-4pm, Altgeld HallCome join Champaign-Urbana's celebration of the spirit of recreational mathematics and fun math puzzles, and the life of math and science writer Martin Gardner! At the occasion of Gardner's 100th birthday the University of Illinois will host a dozen local mathematicians and computer scientists who will present math puzzles, logic puzzles, hexaflexagons, magic tricks, visual paradoxes and much more! It is free and open to members of the public of all ages - no math training required to enjoy the puzzles and the mathematics! For more information, click here. | |

## Workshop "Applications of O-Minimality to Analysis and Number Theory"Passau, September 09-12, 2013 - The goal of the workshop is to bring together people from the areas of analysis and number theory which meet in o-minimality. Intended is a tutorial on the number theoretic problems recently attacked with tools from o-minimality. The heart of the workshop will be significant talks on the newest applications of o-minimality to analysis, analytic geometry and number theory. Read more... | |

## REGS Project: Urbana, June, 2013 - The aim of the project is to study interactions of Logic with other branches of Mathematics. We will study fractal geometry and Cantor sets with the help of tools from Mathematical Logic. We may also consider connections with Diophantine number theory. The precise content will depend on background and interests of the student. Read more... | |

## XIV Graduate Student Conference in Logic (GSCL)Urbana, April 20-21, 2013 - The GSCL is an annual conference organized and run by graduate students in mathematical and philosophical logic. The two-day conference allows any graduate student from around the United States to give a talk on a topic in mathematical or philosophical logic to a large audience of young logicians. This year's conference is to take place at the University of Illinois at Urbana-Champaign during the weekend of April 20-21. Read more... | |

## ASL 2012-2013 Winter Meeting at the JMMThis two day program on Friday and Saturday (Jan. 11th-12th, 2013) will include sessions of contributed papers as well as Invited Addresses by Bradd Hart, McMaster University; Philipp Hieronymi, University of Illinois at Urbana-Champaign; Peter Koellner, Harvard University; Colin McLarty, Case Western Reserve University; Justin Moore, Cornell University; Itay Neeman, University of California Los Angeles; and Christian Rosendal, University of Illinois at Chicago. Read more... | |

## Back2Fields Colloquium - Philipp Hieronymi: Tame Geometry: A tale of two spiralsToronto, October 11, 2012 - The Back2Fields Colloquium Series celebrates the accomplishments of former postdoctoral fellows of Fields Institute thematic programs. Over the past two decades, these programs attracted the rising stars of their fields and often launched very distinguished research careers. As part of the 20th anniversary celebrations, this series of colloquium talks will allow a general mathematical public to become familiar with some of their work. See video... | |

## Annual Gathering for Gardner event celebrates recreational mathematicsUrbana, October 30, 2012 - If Captain Jack Sparrow has 100 gold doubloons, how can he distribute them amongst his ship's crew so that he keeps the largest share and still keep the crew happy enough to avoid walking the plank himself? This is just one of the puzzles posed to attendees of this year's Gathering for Gardner celebration. Read more... |

### Previous events

G4G - Gathering for Gardner, Oct 26, 2012 at Urbana-Champaign

Back to Fields Colloquium, Oct 11, 2012

G4G - Gathering for Gardner, Oct 21, 2011 at Urbana-Champaign

### Links

Ayhan GünaydinChris Miller

Gareth Boxall

Juan Diego Caycedo