The Stacks Project
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Comprehensive free reference on algebraic geometry including affine schemes
More resources on Affine Schemes
Algebraic Geometry
Learn affine schemes and algebraic geometry from Ravi Vakil's Stanford course. Explore fundamentals with detailed lectures and resources.
mathworld.wolfram.com
MathWorld (Wolfram) is a comprehensive online mathematics encyclopedia that provides concise, accessible explanations of mathematical concepts, theorems, and examples. It offers detailed entries on algebraic geometry topics—including affine schemes, spectra of rings, and schemes in general—with definitions, key properties, and references.
The Geometry of Schemes
The Geometry of Schemes - A book resource
ocw.mit.edu
MIT OpenCourseWare is a free, open-access repository of MIT course materials across disciplines. It offers lecture notes, assignments, exams, and video lectures from MIT courses, including algebraic geometry topics that cover affine schemes.
ncatlab.org
nLab is a collaborative, wiki-style knowledge base for advanced mathematics and related areas. It provides in-depth articles, definitions, and references on topics such as affine schemes, algebraic geometry, category theory, and topos theory, with extensive cross-linking between concepts.