
A Passionate CEO and Founder
In his role as CEO of SageMath, Inc., William is at the helm, navigating the future of CoCalc. His responsibilities span delegating tasks, driving profitability, and managing the company’s overall growth strategy. In addition, he maintains a close eye on developments within the cloud-based software industry, assesses company risks to ensure they’re minimized, and ensures that CoCalc remains stable and productive.
Chief Executive Officer and Founder of SageMath, Inc. (2015-present)
William is the CEO and a lead software developer for both the front and back end of CoCalc. His involvement with SageMath development is a testament to his dedication and commitment. His remarkable past career, including a tenure as Professor of Mathematics at the University of Washington, adds richness to his leadership.
Meet William Stein, CEO and Founder of SageMath, Inc.
Get to know the math prodigy behind CoCalc and SageMath, Inc.: William Stein. A Berkeley graduate and an ardent mathematician with over 15 years of experience in teaching and research, William’s passion for number theory and computational science has led him down a remarkable path.
A Man of Academic Origins
William’s academic journey began at the University of California, Berkeley, where he dedicated immense time and energy to using closed-source software like Magma for in-depth analysis and research. Though an admirer of its powerful underlying algorithms, William yearned for more transparent software that didn’t operate as a “black box.” His wish to understand “how things operate under the hood” eventually led him to develop SageMath during his time as Assistant Professor of Mathematics at Harvard.
Journey towards CoCalc
April 2013 marked another momentous chapter in William’s professional life: he launched SageMathCloud, now known as CoCalc. Inspired by his experiences in the academic and computational fields, this web application was designed to enable the collaborative use of open-source software (while eliminating typical installation and package maintenance issues), thus enhancing the teaching and research process in mathematics and data science. CoCalc now operates under a corporate model, making it self-sufficient and capable of growth independent of grants or other external funding.
William’s not all business either. You can catch him making the most of Seattle’s famously dismal winters by splitboarding with his Blue Heeler Bella in the Cascades or skating vert at “the most rad private ramp in Seattle.”
Here is his personal website.
Previous Experience
Tenured Professor of Mathematics at University of Washington (2006-2019)
Tenured Associate Professor of Mathematics at UC San Diego (2005-2006)
Created SageMath Open-Source Software (2004)
Assistant Professor of Mathematics at Harvard University (2000-2005)
Ph.D. in Mathematics from UC Berkeley in Number Theory (2000)

Harald isn’t all work, though. He savors his free time by reconnecting with nature and playing maestro in the kitchen, whipping up enticing Italian meals like pasta, pizza, and lasagna. Additionally, he is an enthusiast of Bitcoin and its cryptic brethren.
Reach him at [email protected] to chat more about his projects or for advice on the perfect marinara sauce.
Chief Technology Officer at SageMath, Inc. (2015-present)
At SageMath, Inc., since 2015, Harald assumes the role of a tech torchbearer, evaluating new technologies and implementing various libraries for CoCalc projects. He ceaselessly strives to fortify SSO services and on-premise installations for CoCalc license holders. His relentless efforts translate into the seamless front-end and back-end software development and maintenance for Sage and CoCalc alike.
Meet Harald Schilly, CTO at SageMath, Inc.
Harald’s life-long dedication to coding and his profound knowledge and dynamic personality have been invaluable in shaping CoCalc’s operations and success.
A software maestro, Harald discovered his passion for coding in his teenage years, experimenting with QBasic on the Microsoft Disk Operating System and advancing onto Turbo Pascal, Visual Basic, Java, and C, among others.
During his studies in Applied Mathematics with a focus on Optimization, he deepened his understanding of the intricate workings of algorithms. As a result, he embraced Java, Python, and later JavaScript as his go-to coding languages. All the while, Harald became a key contributor to the SageMath open-source mathematics software – a testament to his dedication to broadening the horizons of technology and innovation.
Beyond academia, Harald began crafting software solutions for various industry needs. After obtaining his Master’s degree, he embarked on a Ph.D. journey at the University of Vienna while teaching Linux system administration and introducing Python to the undergraduates. Fueled by his passion for industry-relevant solutions, he soon founded his own company.
Fast forward to 2015, Harald became instrumental in CoCalc’s ascend. His role demanded in-depth understanding of Software Engineering, Linux administration, system monitoring, and oversight of the entire Kubernetes cluster. Harald’s responsibilities didn’t just stop there, he managed a towering stack of pre-installed open-source software across all CoCalc projects – a role he fulfills with gusto.
Previous Experience
IT Consultant, Self-Employed (2015-present)
Developer, Sage Open-Source Mathematical Software System (2007-present)
Mathematician, Faculty of Mathematics, University of Vienna (2006-2014)
Research and Development, DAGOPT Optimization Technologies GmbH (2011-2012)
Mag. rer. nat. Mathematics, University of Vienna (1999-2012)
M.S. Mathematics, Mathematics (1999-2008)

Hal is an expert in scientific and exploratory computing with backgrounds in mathematics and medicine. He has also worked with numerous groups for social justice and organizing societal impact/change.
When Hal is not advocating for others or serving in his community through various leadership positions, he enjoys cooking his favorite vegan dishes and taking online courses to enhance his already substantial knowledge base.
Chief Operations Officer at SageMath, Inc. (2016-present)
As Chief Operations Officer, Hal designs and implements various business strategies through planning and setting procedures for the comprehensive goals related to CoCalc’s performance and growth and helps establish policies that promote our company’s culture and vision.
Hal Snyder, COO at SageMath, Inc.
Hal has spent decades working at small and large tech companies and now works on CoCalc’s user support, customer relationship management, documentation, accounting, and occasional Python development.
From 1967-1969 Hal studied at Haverford College near Philadelphia before obtaining his B.S. in mathematics and physics at Lake Forest College in Illinois in 1972. He co-authored numerous works with Professor Tung H. Jeong, such as “Holographic Microscope System Using a Triangular Interferometer” and “The Integration of Motion Pictures into Holograms” before completing his dissertation titled “Factorization of Isometries into Symmetries,” which was published in the Journal of Undergraduate Mathematics. He then attended the University of Chicago as a graduate student and lecturer in mathematics from 1973-1977, eventually gaining his M.S. in mathematics, specializing in group representations and quadratic forms.
Upon completing this goal, Hal enrolled in the Feinberg School of Medicine at Northwestern University and, in 1982, was awarded an M.D. in internal medicine. He has since been the recipient of countless certifications and licenses in various fields of science through edX and Coursera.
Throughout Hal’s career, he has held many prominent positions. To name a few, Hal was a visiting Assistant Professor of Mathematics and Computing/Information Sciences at Roosevelt University, Senior Technical Staff at Mark Williams Company, Senior Technical Staff and V.P. of Hosting Solutions at Vail Systems, Inc., and Senior Information Systems Architect at Orbitz Worldwide.
Previous Experience
Sr. Manager Internal Systems, Expedia, Inc. (2016)
Senior Information Systems Architect/Technology, Orbitz Worldwide (2010-2015)
Systems Architect, Northwestern University Department of Preventive Medicine (2009-2010)
Senior Technical Staff and V.P., Hosting Solutions, Vail Systems, Inc. (1996-1998) & (1999-2007)
M.S. Mathematics and Physics, University of Chicago (1973-1977)

A fiery passion for implementing data-driven decision-making in government, industry, and academia. Blaec’s advocacy exemplifies his research interests — applied mathematics and numerical modeling of multiscale geophysics.
His dedication to academic communities is evident through his past roles, notably as the Student Chapter Secretary of the Society of Industrial and Applied Mathematics. Now, it’s hard to even name a community he’s not involved in.
Chief Sales Officer at SageMath, Inc. (2022-present)
If you would like to discuss computational applied mathematics, software development/integration opportunities, or possible partnerships with SageMath, don’t hesitate to get in touch with Blaec via email at [email protected]!
Meet Blaec Bejarano, CSO at SageMath, Inc.
Graduating in 2021 with an M.S. in Mathematics from Oregon State University, Blaec uniquely combines advanced mathematical modeling skills with a thriving energy for mountain climbing and music. His academic expertise focuses on applying numerical analysis and partial differential equations to model physical phenomena.
Blaec’s foundation in modern teaching methods, gained through his years as a teaching assistant and instructor, complements his current role at SageMath, where his responsibilities span from increasing CoCalc’s user base through innovative market penetration strategies to social media/advertising campaigns. Moreover, blaec drives opportunities for CoCalc by demonstrating the platform’s most recent features via live demos at premier conferences like the International Congress on Industrial and Applied Mathematics and the International Conference on Machine Learning.
Beyond academic spheres, Blaec is actively engaged in several industry and business societies, including the Seattle Chamber of Commerce, the National Small Business Association Leadership Technology Council, and open-source technology/startup communities like NumFocus and Startup Grind. Blaec directs corporate alliances among his many roles, leading the bid to fuse other proprietary software like MATLAB into the open-source ecosystem.
Even amidst his busy schedule, Blaec finds time for adventure and creativity. Lovingly known as one of the SageMath resident mountaineers, Blaec often scales the Cascade volcanoes of the Pacific Northwest (and can otherwise be found at home writing songs alongside his cat Fushigi).
Previous Experience
Tutor, Cascade Enrichment (2022)
Instructor of Record, Oregon State University (2019-2021)
Graduate Teaching Assistant, Oregon State University (2018-2021)
M.S. Mathematics, Oregon State University (2018-2021)
B.A History and B.S. Mathematics, University of West Florida (2013-2017)