Simon Rubinstein-Salzedo is the founder and one of the instructors at Euler Circle. Simon received his PhD at Stanford University in 2012 under the direction of Akshay Venkatesh in algebraic number theory. He has done research in many areas of mathematics, including number theory, algebraic geometry, combinatorics, game theory, probability, and complex analysis. Before founding Euler Circle, Simon taught mathematics at Stanford University and Dartmouth College.

In addition to his teaching at universities, Simon has been teaching mathematics to advanced middle-school and high-school students for over a decade and is extremely popular among his students. He is currently the lecturer for Program II at the Stanford University Mathematics Camp (SUMaC), where he teaches algebraic topology.  He has worked at The Art of Problem Solving and has taught at many math events and run many math circles in the Bay Area. He is also the coach of the San Francisco Bay Area ARML team, which won the national championship for three consecutive years. His greatest claim to fame in life is probably having a factoring trick named after him.

Simon has also successfully directed mathematics research projects for high-school students, leading to five original papers coauthored with students so far, and more projects are currently in progress. His papers can be found on his website. Please contact him at

Outside of mathematics, Simon is also an avid musician, chess player, and calligrapher.

maximMaxim Gilula received his undergraduate degree at UC Irvine before moving to Philadelphia for grad school in math at UPenn. His research included infinite series, oscillatory integrals, and decoupling. After working as a visiting assistant professor at Michigan State University, he made his way back home to the Bay Area to join Stanford OHS.

He likes to play tennis and video games.

Teaching Assistants

aaronkauferAaron Kaufer is a junior at Stanford studying mathematics and computer science. He is interested in algebra and number theory. He loves tutoring and works as a peer tutor for Stanford’s math department. He has done research in commutative algebra and written a paper and given a talk on his results. Outside of math, he likes archery and Rubik’s cubes.

aaronlinAaron Lin is a recent graduate from MIT in math and computer science, and is especially interested in topics surrounding topology, combinatorics, and computational complexity theory. He is always looking for new books to read, puzzle games, and someone to play Go (Weiqi) with.

alexdeweeseAlex DeWeese is currently an undergraduate computer science student at UC Berkeley. His primary research interests are in machine learning and its applications. Aside from academics he enjoys drawing and learning languages (Korean and Japanese).

alexanderAlexander Richardson is a senior at UC Berkeley majoring in mathematics with a minor in physics. Currently doing research in differential geometry, but with interests in analysis, combinatorics, differential equations, algebra. Essentially any math class he has taken seems to become a new interest.

Outside of academia, his interests are hiking, rock climbing, singing, theatre, musical theatre, and seeking new experiences.

aliceyangAlice Yang is an undergraduate senior at Stanford studying mathematics. Her interests include areas in probability and optimization/dynamical systems. She has previously taught students in both competitive and non-competitive math. Outside of math, she enjoys playing and listening to music.

annie chenAnnie Chen is an undergraduate at Stanford University studying mathematics. Her interests include analysis, probability, and combinatorics. She has done research in arithmetic dynamics and probability theory and has written a paper and given a conference presentation on her work. In addition, she has previously tutored many advanced middle and high school students in math. In her free time, Annie enjoys playing tennis and card games.

AnnikaMauroAnnika Mauro is an undergraduate studying mathematics at Stanford. She is interested broadly in math, especially complex analysis, algebraic topology, and combinatorics, and has done research in discrete math. She is also enthusiastic about computer science and physics. In her free time, she enjoys reading, spending time outdoors, and drawing.

benhellerBen Heller is an undergraduate at Stanford studying mathematics. His interests range over virtually all branches of math, but has a soft spot for mathematical logic, analysis, and differential topology. He has done research in probability theory and has experience tutoring undergraduates in the Stanford math department’s peer tutoring program. Aside from math, he enjoys tinkering with Linux and listening to music.

bryanhuBryan Hu is a graduate student at UCSD studying mathematics. His interests include number theory, algebraic geometry, and combinatorics. He was previously an assistant instructor at the Los Angeles Math Circle. Outside of math, Bryan enjoys basketball and all kinds of games.

caseyCasey Wojcik is a graduate student at Stanford, researching topological photonics. He has broad interests in mathematics and physics, and especially likes to see how diverse concepts from math can help explain simple and universal physical phenomena. In his free time, he enjoys birding and other outdoor activities.

CatherineWahlenmayerCatherine Wahlenmayer is a rising second year graduate student at UC San Diego. She is interested in learning more about discrete geometry, combinatorics and math education. She has worked as an online tutor for Larson Texts, Inc. and as a TA at Gannon University and UCSD, and she would like to pursue a career in teaching. Outside of math, Catherine enjoys cooking and baking and is looking forward to skydiving for the first time.

clydeClyde Huibregtse graduated from MIT in 2020 with degrees in Physics and Mathematics for Computer Science. He is currently a software engineer at a nuclear energy startup in Sunnyvale called Oklo. He works at the intersection of scientific computing and machine learning in the development of non-linear models for core dynamics. In college, he was an NCAA water polo player and still spends his time training and playing competitively in the Bay Area.

dominickDominick Joo is an undergraduate at Brown studying mathematics. He is particularly interested in geometry and topology, as well as secondary mathematics education. His other academic interests include linguistics and music. In his free time, he plays chess, does crosswords and reads.

dowonDowon Kim is a recent graduate from UC Berkeley in statistics and data science. His interests include probability theory, machine learning and stochastic processes. Outside of school, he enjoys golf, snowboarding, and history.

ericfrankelEric Frankel is a sophomore at Stanford studying mathematics. He is interested in analysis, probability, combinatorics, and dynamical systems, and has done research in probability theory. Eric is a board member on Stanford’s Math Organization and has tutored students in competitive and non-competitive math. Outside of math, Eric likes exercising, eating, coding, and getting bad haircuts.

erickimEric Kim is a recent graduate from Stanford University in mathematics. His interests include algebra, number theory, functional analysis, probability, and differential equations. He has done research in complex analysis and has graded for undergraduate courses. Aside from math, he enjoys singing and solving Rubik’s cubes.

eyobtsegayeEyob Tsegaye is a junior at Stanford studying mathematics. His interests include algebra and combinatorics. He has research experience in additive combinatorics, probability theory, and finite group theory. Additionally, he has previously tutored several high schoolers. Outside of math, he enjoys reading, listening to music, and playing smash bros.

gautamGautam Manohar is a freshman at Stanford studying mathematics. He enjoys analysis, differential equations, and number theory. He is also interested in mathematical writing and communication, as well as computer science, especially algorithms and data structures. In his free time, he likes learning languages, following basketball, and writing.

javierJavier Echevarría is a senior at Stanford University studying mathematics and computer science. He is interested in partial differential equations, differential geometry, and mathematical physics. Besides grading undergraduate level courses, he has also been a tutor for fellow students ever since high school. In his free time, he enjoys swimming and playing the piano.

jaysinghJaydeep Singh is a senior at Stanford studying mathematics. He is interested in the intersections of mathematics and physics, as they manifest in probability, PDE, and geometric analysis. He has research experience in mathematical general relativity and gauge theory, and has worked as a calculus peer tutor at Stanford. Outside of school, he enjoys baking, playing tennis, and listening to music.

jiazhenJiazhen Tan is a graduate student at UC Berkeley studying mathematics. Her interests include number theory, algebra, functional analysis, and classical geometry. As an undergrad, she organized puzzle session for Cornell’s math club and tutored at the department-run Math Support Center. She also worked as a counselor at Ross and PROMYS during the summers. She likes making polyhedral models (modular origami, balloon stuff), learning ice skating, blueberries, and the number 1207.

joshJosh Zeitlin is a student at Yale University majoring in mathematics and was a former Euler Circle student from 2019 to 2021. His main pure mathematical interests are probability theory and algebraic number theory, yet is also interested in computer science and machine learning. Outside of math, Josh likes to take long hikes, solve puzzles and watch basketball.

karengeKaren Ge is an undergraduate at Stanford who hopes to improve mathematics education. She is interested in areas of number theory, algebraic topology, and cryptography. Karen has extensive experience tutoring and coaching in both competitive and non-competitive math. Outside of math, she loves playing ultimate frisbee, being swept away by the wonders of orchestral music, and writing poetry.

katywooKaty Woo is a senior studying mathematics. She is interested in and has done research in number theory and cryptography. She was the president of Stanford’s student math organization and is currently a peer adviser for the math department. She has also been a counselor for Stanford University Mathematics Camp and a course assistant for a cryptography class in the CS department. Outside of math, she enjoys dancing and origami.

kishanKishan Jani is a co2025 undergraduate student at UC Berkeley studying math. Broadly, his interests lie in probability theory, complex analysis, and number theory, and he is currently pursuing some research related to Markov chains. Kishan enjoys counting primes, doing integrals, and learning about primality-proving algorithms. Outside of math, he also really enjoys physics and linguistics. He loves teaching, and as a former Euler Circler, he is really excited to be a TA and share fun math with others!

mateoMateo Attanasio is an undergraduate at Stanford studying mathematics. His interests include algebra, number theory, and topology. He has experience as a peer tutor in the Stanford maths department. Outside of mathematics, interests include rock climbing and history.

matinMatin “Mat” Ghavamizadeh recently graduated with highest honors from UC Berkeley with degrees in Electrical Engineering and Computer Science (EECS) and Applied Mathematics with a focus on probability theory. Currently, he is a visiting researcher at MIT Probabilistic Computing Project (ProbComp). Before starting his PhD at MIT, Matin is taking the next year off to finish Part III of the mathematical tripos in statistics at the University of Cambridge. His mathematical interests are analysis, probability theory, statistics, and computation -especially probabilistic computation. Besides math and computers, Matin enjoys reading, thinking, cooking, and comedy.

mayaMaya Sankar is a first-year PhD student in mathematics at Stanford. Her interests lie in graph theory and combinatorics. Outside of school, Maya loves to play music, read, and knit, and is delighted to be back home in California where she can enjoy the sun all year round.

mozhganMozhgan Mirzaei is a recent graduate from UC San Diego in math. In particular, she is interested in Combinatorics, Computational Geometry, and Graph Theory. Besides math, Mozhgan loves exercising, playing chess, and painting.

nicklasNicklas Majamaki is a junior at UC Berkeley studying Electrical Engineering & Computer Science. He is interested in probability, number theory, and deep learning. He has tutored for both high school and undergraduate courses. Outside of academics, he is on the Cal Triathlon team and enjoys hiking, going to the beach, and eating good food.

nik_castroNik Castro is a senior at Stanford studying mathematics.  His interests include real analysis, probability, algebraic topology, and algebraic number theory.  He has graded for both undergraduate and graduate level courses, and was a counselor at the Stanford University Mathematics Camp.  Outside of math, he enjoys practicing martial arts.

nikhilNikhil Sahoo is a recent graduate from UC Berkeley, where he earned a BA in math. His primary mathematical interests are in differential topology, but he has done research projects in symplectic topology, Schubert calculus, and Minkowski geometry. Nikhil has also lectured and graded for the Berkeley Math Circle since 2018, where he greatly enjoys the opportunity to share interesting mathematics with students of all levels. Outside of studying and teaching, Nikhil enjoys hiking and rock climbing.

nina_zubrilinaNina Zubrilina is an undergraduate at Stanford studying mathematics. She enjoys combinatorics, analytic number theory, analysis, geometry and anything having to do with sphere packing. She has done research in combinatorics and number theory and has written four papers on her work.

Besides Euler circle, her teaching experience includes being a TA for other math circles, TAing a class in Moscow High School #57, being a counselor and TA in a summer math camp, and giving a series of lectures in the Moscow Branch of the Higher School of Economics.

nitya_maniNitya Mani is an undergraduate studying mathematics at Stanford University. She is excited about problems in algebraic number theory and extremal combinatorics and has done research in both areas. Some current areas she is learning more about include geometric measure theory and local class field theory. In addition to being a teaching assistant at Euler Circle for the past 3 years, Nitya coordinates the student peer tutoring program for the Stanford mathematics department and has graded many Stanford math classes.

niven.jpeg Niven Achenjang is a senior at Stanford, studying mathematics. His mathematical interests include algebraic number theory, algebraic topology, and complex geometry, and he has published research in number theory. At Stanford, he has graded for and tutored students in math classes, as well as been a counselor and TA for the Stanford University Mathematics Camp. Outside of math, Niven enjoys video games, sports of all kinds, and performing with the Stanford Jump Rope Team.

onyebuchiOnyebuchi Ekenta is a math graduate student at UC Berkeley. He studies computational linear algebra and scientific computing. He’s also interested in the field of computational complexity theory. For hobbies, he likes watching anime, and playing around with computer programs and circuits.

PeteRigasPete Rigas is a recent graduate of Cornell University, having received a Bachelor’s degree, summa cum laude, in Mathematics, and a Masters’ degree in Statistics. He is interested in probability theory, statistical mechanics, variational quantum computing, synthetic biology, and prognostics of autonomous space vehicles. He has conducted research in all of these areas, with a particular emphasis on quantifying the sharpness of crossing probability estimates for the dilute Potts model, which shares connections with the Loop O(n) model, in addition to several forthcoming works on different statistical models. In his free time, he likes to run, go to the beach, and explore different parts of Southern California.

quinn_photoQuinn Greicius is a senior at Stanford studying mathematics. He is interested in algebraic geometry, number theory, and algebraic topology, and has done research on Galois representations arising from abelian varieties. He has previously taught classes in algebra and number theory for advanced high schoolers in the Bay Area. In his free time, Quinn enjoys playing the piano, reading, and playing soccer.

rachanaRachana Madhukara is an undergraduate at MIT studying mathematics. She is primarily interested in elementary and analytic number theory and has research experience in these areas. Outside of math, Rachana likes going to escape rooms, rock climbing, cooking, and traveling.

rajeeRajashree (Rajee) Agrawal is a freshman at George Mason University. Previously, Rajee dropped out of school in India to pursue independent learning. She is currently leveraging her education experience to run experiments in teaching, particularly She is most excited about logic, category theory, and combinatorics. Besides math, Rajee is interested in robustness in machine learning, free market economics, and financial engineering. She spends her leisure time singing Hindustani classical, swing dancing, cooking, and doing group meditation with friends.

richardRichard Yi just graduated from MIT, majoring in math and physics, and will pursue a PhD in math at UC San Diego starting this fall. He is interested in number theory and algebraic geometry. He has coached several students in competition math. Besides doing math, he has been spending his time this summer playing chess, thinking about philosophy, and reading different kinds of books.

ryansmithRyan Smith is a master’s student in computer science at Stanford. His interests are in cryptography, computational complexity theory, and algebraic number theory. He has TA experience at the Stanford University Mathematics Camp as well as the computer science department at Stanford. Outside of math he enjoys reading, musical theater, and games of all kinds.

sawyerSawyer Dobson is an undergraduate student at Stanford studying mathematics. He is primarily interested in number theory and cryptography, and he has experience writing problems for math competitions. Before coming to Stanford, he taught his high school math club in San Francisco. Outside of math, Sawyer enjoys programming, playing volleyball, and playing board games.

sawyerSawyer Robertson is currently a first-year math PhD student at the University of California, San Diego. His research interests are generally geared towards combinatorics and applications to data science, with special emphasis on spectral graph theory.

shardulShardul Chiplunkar is a ’22 undergrad at MIT studying mathematics and computer science. His mathematical interests include logic, formal systems, theory of computation, and programming language theory; his other academic interests include linguistics and computational cognitive science. He is currently doing research in formal verification and program synthesis. He also enjoys listening to and creating music (especially Hindustani classical), teaching, and spinning fire.

sherrySherry Sarkar is a senior computer science major from Georgia Tech. Her research interests are combinatorics, theoretical computer science, and discrete geometry. She has several papers and conference talks in these areas. Sherry also has TAed several math and CS courses at Georgia Tech. Outside of research, she boulders and watches anime.

soniachuSonia Chu is a freshman at Stanford University. She’s interested in a wide variety of areas in math, along with interdisciplinary studies between math and other fields. Sonia has taught students ranging from elementary school to high school, in both competition and non-competition math. In addition, she has authored lab manuals for college cryptography courses. Outside of math, she enjoys reading, playing the clarinet, and skiing.

suryaprakashSurya Vengadesan is an undergrad at UC Berkeley studying computer science and math. His interests lie in optimization and theoretical computer science. Surya also enjoys reading and internet surfing. Check out his writings and notes at

timwuTim Wu is an undergraduate at Stanford studying mathematics. His interests include number theory, combinatorics, and graph theory, and he has done research in graph theory. Before joining Euler Circle, Tim ran and taught a math circle back home in Michigan. Outside of math, he enjoys listening to music and trading stocks.

tylerTyler Shibata is a sophomore at Stanford studying mathematics. Though his mathematical interests span a variety of branches, he particularly enjoys studying linear algebra, stochastic processes, and real analysis. Despite having no formal interest in mathematics prior to college, he fell in love with the motivations behind certain topics after watching some inspiring 3Blue1Brown videos. Outside of math, he likes to cox for Stanford Men’s Rowing, cook and eat delicious foods, and play the saxophone.

varunVarun Srivastava is a UC Berkeley undergraduate studying math and computer science. He is a former member of Euler Circle where he developed a broad interest in combinatorics, algebra, and number theory.
Outside of math, he enjoys playing the guitar, exercising, and reading.

williamxiWilliam Xi is an undergraduate at Stanford studying mathematics and computer science. He is interested in all kinds of mathematics, especially algebra, number theory, and combinatorics. He has tutored students over the years in both competitive and non-competitive math and has graded for several online math classes. Outside of math, William enjoys coding, physics, playing basketball, and eating.

yelena_mandelshtamYelena Mandelshtam is a senior at Stanford studying mathematics. She has been a TA at Euler Circle since 2016, and was a TA at the Euler Camp in Irvine in winter 2017-18. In addition to Euler Circle, Yelena has experience teaching a math circle at her Russian school when she was in high school, being a counselor at the Stanford University Mathematics Camp, and tutoring students individually. Her primary research interests are combinatorics and analysis. She has done research in mathematical biology, combinatorics, and ergodic theory and has written five papers on her work. Outside of math, Yelena enjoys rock climbing, playing board games, and reading and writing poetry.

yuzu_photoYuzu Ido is a sophomore at Stanford studying mathematics and music. She is interested in multiple areas of math, currently with an emphasis on algebra. She has done research on integer forms and elliptic curves and is a peer tutor for the Stanford Undergraduate Mathematical Organization. Outside of math, she enjoys making music, taking interesting courses in a variety of subjects, and eating good food.

zizaiZizai Cui is an undergrad at Duke. He wants to study the ideas and forces that have shaped the contemporary society. His goal is to be a Renaissance Man.

He intends to devote his life to the pursuit of Truth and Beauty, and Maths seems to be a combination of the two!

More information can be found in his website.

zoe_himwichZoe Himwich is a math major in her senior year at Stanford. She has been a TA at Euler Circle since Winter 2018. Her other teaching experience includes TA-ing at Stanford Math Circle and grading undergraduate math classes. She has done research in several areas of mathematics, including graph theory, topological quantum field theories, and the mathematics of phylogenetics. When not doing math, Zoe studies English literature and enjoys learning new languages.