
When William is away from the computer, you can find him skateboarding on his vert ramp (the most significant private ramp in Seattle) and enjoying the scenery of the Pacific Northwest while hiking, mountaineering, or split boarding with his companion named Bella, a blue heeler with a big personality.
Chief Executive Officer and Founder of SageMath, Inc. (2015-present)
As CEO, William is responsible for many aspects of CoCalc’s development. Some of these include delegating tasks and directing CoCalc’s agenda, driving profitability, and managing the company’s overall growth strategy. He effectively communicates CoCalc’s vision with shareholders, institutions, and the general public while evaluating the work of other executive leaders.
Moreover, William maintains a consistent vigilance of the market landscape by monitoring developments within the cloud-based software industry, assessing company risks to ensure they are minimized, and ensuring that CoCalc remains stable and productive.
In addition to William’s functions as CEO and Founder of SageMath, Inc., he also serves as a lead software developer for both the front and back end of CoCalc. In addition, he remains involved with the development of SageMath.
William Stein, CEO and Founder of SageMath, Inc. and creator of SageMath and CoCalc
Before CoCalc, William spent 15 years teaching and doing research at Berkeley, Harvard, UC San Diego, and the University of Washington as a pure mathematician specializing in number theory.
During this time, William discovered he could contribute significantly to the mathematical community by developing SageMath while working as an Assistant Professor of Mathematics at Harvard.
As a graduate student at the University of California Berkeley, William was deeply involved with the closed-source software Magma. Unfortunately, after being one of its major proponents, he became disenfranchised by its closed-source philosophy, which requires academic researchers to operate under restrictions that essentially constitute a “black box.” While the underlying algorithms of Magma were powerful, he could not justify the immense dedication of time and analysis that goes into Ph.D.-level research without having a thorough understanding of “how things operate under the hood.” Magma also had no way for its code to be easily modified for an individual’s specific requirements.
Based on his extensive experience within the academic and computational communities, William launched the CoCalc web application in April 2013 under the name SageMathCloud, to make it easier to collaboratively use open-source software for teaching and performing research in mathematics and data science.
William decided it would be best to release CoCalc under a company model so it could be self-sufficient and grow without needing grants or other external funding. However, this resolution also came under the pretense of giving back to the open-source software community once CoCalc was well-established and profitable.
William honestly believes that through the collaboration that CoCalc enables, we can unify the communities of mathematics and scientific computing to tackle the world’s most substantial challenges and ultimately push us closer toward the frontier of technological advancement.
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 occasionally enjoys visiting nature and relishes his time in the kitchen -creating Italian dishes such as pasta, pizza, and lasagne. He is also quite knowledgeable regarding Bitcoin and other various cryptocurrencies.
Chief Technology Officer at SageMath, Inc. (2015-present)
As the Chief Technology Officer of SageMath, Inc., Harald is in charge of evaluating new technology and implementing various libraries for CoCalc projects. In addition, he is working hard to provide SSO services and on-premise installations for CoCalc license holders. He is also responsible for general frontend and backend software development and maintenance for Sage and CoCalc.
Harald Schilly, CTO at SageMath, Inc.
Initially, Harald discovered his passion for coding as a teenager by toying with QBasic in the Microsoft Disk Operating System. From that point, his journey as a software developer got him involved with Turbo Pascal, Visual Basic, Java, C, and other programming languages.
While Harald studied applied mathematics focusing on optimization, he gained a much deeper understanding of algorithms’ workings. As a result, Java, Python, and later JavaScript became his languages of choice, and during that time, he became a significant contributor to SageMath open-source mathematics software.
Aside from his experience while attending university, Harald was involved in developing software solutions for various industries. After finishing his master’s degree, he became a perpetual Ph.D. candidate at the University of Vienna, where he taught several Linux system administration lectures and introduced Python to undergraduates. Then, drawn into the industry, he started his own company.
In 2015, Harald became deeply involved in CoCalc. To keep the quickly growing online service up and running, he not only deepened his knowledge in Software Engineering, Linux administration, and system monitoring but also became proficient in designing and managing the entire Kubernetes cluster. Harald is also responsible for managing the massive stack of pre-installed open-source software, which is available in all CoCalc projects.
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)

In addition to meeting the demands of CoCalc’s high ticket sales, Blaec is an avid mountaineer. Often frequenting the Cascade volcanoes of the Pacific Northwest and beyond, he finds great pleasure in ice climbing and occasionally travels internationally to climb.
Blaec is also an accomplished guitarist and songwriter, with most of his experience from his time in Northwest Florida.
Chief Sales Officer at SageMath, Inc. (2022-present)
As Chief Sales Officer, Blaec directs and leads all activities related to revenue generation for SageMath, Inc. His everyday duties include increasing CoCalc’s client base through market penetration strategies, social media, and advertising campaigns and providing information on CoCalc’s newest products and features via demos and our newly created series of tutorials and blog posts.
Blaec Bejarano, CSO at SageMath, Inc.
Recently graduating with his M.S. in mathematics from Oregon State University, Blaec is the newest member of the SageMath, Inc. team, serving as Chief Sales Officer for the product/service CoCalc.
Blaec’s studies focus primarily on the applied mathematical modeling of physical phenomena, namely consolidation theory, and hysteresis, using numerical analysis and ordinary differential equations. His expository paper “Consolidation with Hysteresis in Sedimentary Basins” was written under the guidance of Dr. Ralph Showalter and Dr. Malgorzata Peszynska at Oregon State University.
Throughout his experience as a graduate teaching assistant and instructor, Blaec has gained a fundamental understanding of modern teaching-based needs and provides a unique and youthful perspective to the company. In addition, he became proficient in several programming languages for his research in numerical modeling and experimentation. He continues to aspire to one day receive his Ph.D. in Earth and Space Science with a specialization in applied mathematics by performing analysis about glacial modeling in alpine settings.
Aside from his attendance at Oregon State University, Blaec is an alumnus of the University of West Florida with a B.S. in mathematics and a B.A. in history. He has served his various academic communities in several leadership roles, the most recent being Student Chapter Secretary of the Society of Industrial and Applied Mathematics. In addition, he is a regular conference participant for SIAM’s Pacific Northwest section. He admires the camaraderie he has found between the scientifically oriented professionals at these events and their resolve to solve some of the world’s most demanding issues.
Blaec is new to the Seattle area and is open to networking opportunities with other like-minded professionals in computational applied mathematics, software development, and tech sales. Please reach out to connect with him!
Previous Experience
Tutor, Liddane Tutoring and Learning Services (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)