10 Commutative Algebra
- Section 10.1: Introduction
- Section 10.2: Conventions
- Section 10.3: Basic notions
- Section 10.4: Snake lemma
- Section 10.5: Finite modules and finitely presented modules
- Section 10.6: Ring maps of finite type and of finite presentation
- Section 10.7: Finite ring maps
- Section 10.8: Colimits
- Section 10.9: Localization
- Section 10.10: Internal Hom
- Section 10.11: Characterizing finite and finitely presented modules
-
Section 10.12: Tensor products
- Definition 10.12.1
- Lemma 10.12.2
- Lemma 10.12.3
- Lemma 10.12.4
- Lemma 10.12.5
- Definition 10.12.6
- Lemma 10.12.7
- Lemma 10.12.8
- Lemma 10.12.9: Tensor products commute with colimits
-
Lemma 10.12.10
- Equation 10.12.10.1
- Remark 10.12.11
- Example 10.12.12
- Remark 10.12.13
- Lemma 10.12.14
- Lemma 10.12.15
- Lemma 10.12.16
- Section 10.13: Tensor algebra
- Section 10.14: Base change
- Section 10.15: Miscellany
- Section 10.16: Cayley-Hamilton
- Section 10.17: The spectrum of a ring
- Section 10.18: Local rings
- Section 10.19: The Jacobson radical of a ring
-
Section 10.20: Nakayama's lemma
- Lemma 10.20.1: Nakayama's lemma historical remark reference
- Lemma 10.20.2
- Lemma 10.20.3
- Section 10.21: Open and closed subsets of spectra
- Section 10.22: Connected components of spectra
- Section 10.23: Glueing properties
- Section 10.24: Glueing functions
- Section 10.25: Zerodivisors and total rings of fractions
- Section 10.26: Irreducible components of spectra
- Section 10.27: Examples of spectra of rings
- Section 10.28: A meta-observation about prime ideals
- Section 10.29: Images of ring maps of finite presentation
- Section 10.30: More on images
- Section 10.31: Noetherian rings
- Section 10.32: Locally nilpotent ideals
- Section 10.33: Curiosity
- Section 10.34: Hilbert Nullstellensatz
-
Section 10.35: Jacobson rings
- Definition 10.35.1
- Lemma 10.35.2
- Lemma 10.35.3
- Lemma 10.35.4
- Lemma 10.35.5
- Lemma 10.35.6
- Example 10.35.7
- Example 10.35.8
- Lemma 10.35.9
- Lemma 10.35.10
- Theorem 10.35.11
- Lemma 10.35.12
- Example 10.35.13
- Lemma 10.35.14
- Example 10.35.15
- Example 10.35.16
- Lemma 10.35.17
- Lemma 10.35.18
- Proposition 10.35.19
- Lemma 10.35.20
- Lemma 10.35.21
- Lemma 10.35.22
- Example 10.35.23
- Example 10.35.24
-
Section 10.36: Finite and integral ring extensions
- Definition 10.36.1
- Lemma 10.36.2
- Lemma 10.36.3
- Lemma 10.36.4
- Lemma 10.36.5
- Lemma 10.36.6 slogan
- Lemma 10.36.7
- Lemma 10.36.8
- Definition 10.36.9
- Lemma 10.36.10
- Lemma 10.36.11
- Lemma 10.36.12 slogan
- Lemma 10.36.13 slogan
- Lemma 10.36.14
- Lemma 10.36.15
- Lemma 10.36.16
- Lemma 10.36.17
- Lemma 10.36.18
- Lemma 10.36.19
- Lemma 10.36.20
- Lemma 10.36.21
- Lemma 10.36.22
- Lemma 10.36.23
- Lemma 10.36.24
- Section 10.37: Normal rings
- Section 10.38: Going down for integral over normal
-
Section 10.39: Flat modules and flat ring maps
- Definition 10.39.1
- Lemma 10.39.2
- Lemma 10.39.3
- Lemma 10.39.4
- Lemma 10.39.5
- Lemma 10.39.6
- Lemma 10.39.7
- Lemma 10.39.8
- Lemma 10.39.9
- Lemma 10.39.10
- Lemma 10.39.11: Equational criterion of flatness
- Lemma 10.39.12
- Lemma 10.39.13
- Lemma 10.39.14
- Lemma 10.39.15 slogan
- Lemma 10.39.16
- Lemma 10.39.17
- Lemma 10.39.18
- Lemma 10.39.19
- Lemma 10.39.20
- Section 10.40: Supports and annihilators
- Section 10.41: Going up and going down
- Section 10.42: Separable extensions
- Section 10.43: Geometrically reduced algebras
- Section 10.44: Separable extensions, continued
- Section 10.45: Perfect fields
- Section 10.46: Universal homeomorphisms
- Section 10.47: Geometrically irreducible algebras
- Section 10.48: Geometrically connected algebras
- Section 10.49: Geometrically integral algebras
- Section 10.50: Valuation rings
- Section 10.51: More Noetherian rings
- Section 10.52: Length
- Section 10.53: Artinian rings
- Section 10.54: Homomorphisms essentially of finite type
- Section 10.55: K-groups
- Section 10.56: Graded rings
- Section 10.57: Proj of a graded ring
- Section 10.58: Noetherian graded rings
- Section 10.59: Noetherian local rings
- Section 10.60: Dimension
- Section 10.61: Applications of dimension theory
- Section 10.62: Support and dimension of modules
-
Section 10.63: Associated primes
- Definition 10.63.1
- Lemma 10.63.2
- Lemma 10.63.3
- Lemma 10.63.4
- Lemma 10.63.5
- Proposition 10.63.6
- Lemma 10.63.7 slogan
- Lemma 10.63.8
- Lemma 10.63.9
- Lemma 10.63.10
- Lemma 10.63.11
- Remark 10.63.12
- Lemma 10.63.13
- Lemma 10.63.14
- Lemma 10.63.15
- Lemma 10.63.16
- Lemma 10.63.17
- Lemma 10.63.18
- Lemma 10.63.19
- Lemma 10.63.20
- Section 10.64: Symbolic powers
- Section 10.65: Relative assassin
- Section 10.66: Weakly associated primes
- Section 10.67: Embedded primes
- Section 10.68: Regular sequences
- Section 10.69: Quasi-regular sequences
- Section 10.70: Blow up algebras
- Section 10.71: Ext groups
- Section 10.72: Depth
-
Section 10.73: Functorialities for Ext
- Lemma 10.73.1
-
Section 10.74: An application of Ext groups
- Lemma 10.74.1
- Section 10.75: Tor groups and flatness
- Section 10.76: Functorialities for Tor
- Section 10.77: Projective modules
- Section 10.78: Finite projective modules
- Section 10.79: Open loci defined by module maps
- Section 10.80: Faithfully flat descent for projectivity of modules
- Section 10.81: Characterizing flatness
- Section 10.82: Universally injective module maps
- Section 10.83: Descent for finite projective modules
- Section 10.84: Transfinite dévissage of modules
- Section 10.85: Projective modules over a local ring
- Section 10.86: Mittag-Leffler systems
-
Section 10.87: Inverse systems
- Lemma 10.87.1
- Section 10.88: Mittag-Leffler modules
- Section 10.89: Interchanging direct products with tensor
- Section 10.90: Coherent rings
- Section 10.91: Examples and non-examples of Mittag-Leffler modules
- Section 10.92: Countably generated Mittag-Leffler modules
- Section 10.93: Characterizing projective modules
-
Section 10.94: Ascending properties of modules
- Lemma 10.94.1
- Section 10.95: Descending properties of modules
- Section 10.96: Completion
- Section 10.97: Completion for Noetherian rings
- Section 10.98: Taking limits of modules
-
Section 10.99: Criteria for flatness
- Lemma 10.99.1
- Lemma 10.99.2
- Lemma 10.99.3
- Lemma 10.99.4
- Lemma 10.99.5
- Lemma 10.99.6
- Lemma 10.99.7: Local criterion for flatness
- Lemma 10.99.8
- Lemma 10.99.9
- Lemma 10.99.10: Variant of the local criterion
- Lemma 10.99.11
- Lemma 10.99.12
- Lemma 10.99.13
- Lemma 10.99.14
- Lemma 10.99.15: Critère de platitude par fibres; Noetherian case
- Section 10.100: Base change and flatness
- Section 10.101: Flatness criteria over Artinian rings
- Section 10.102: What makes a complex exact?
- Section 10.103: Cohen-Macaulay modules
- Section 10.104: Cohen-Macaulay rings
- Section 10.105: Catenary rings
- Section 10.106: Regular local rings
- Section 10.107: Epimorphisms of rings
- Section 10.108: Pure ideals
- Section 10.109: Rings of finite global dimension
- Section 10.110: Regular rings and global dimension
-
Section 10.111: Auslander-Buchsbaum
- Proposition 10.111.1
- Section 10.112: Homomorphisms and dimension
- Section 10.113: The dimension formula
- Section 10.114: Dimension of finite type algebras over fields
- Section 10.115: Noether normalization
- Section 10.116: Dimension of finite type algebras over fields, reprise
-
Section 10.117: Dimension of graded algebras over a field
- Lemma 10.117.1
-
Section 10.118: Generic flatness
- Lemma 10.118.1
- Lemma 10.118.2 slogan
-
Lemma 10.118.3
- Equation 10.118.3.1
- Equation 10.118.3.2
- Lemma 10.118.4
- Lemma 10.118.5
- Lemma 10.118.6
- Lemma 10.118.7
- Section 10.119: Around Krull-Akizuki
-
Section 10.120: Factorization
- Definition 10.120.1
- Lemma 10.120.2
- Lemma 10.120.3
- Definition 10.120.4
- Lemma 10.120.5
- Lemma 10.120.6
- Lemma 10.120.7: Nagata's criterion for factoriality reference
- Lemma 10.120.8
- Lemma 10.120.9
- Lemma 10.120.10
- Lemma 10.120.11
- Definition 10.120.12
- Lemma 10.120.13
- Definition 10.120.14
- Lemma 10.120.15
- Lemma 10.120.16 slogan
- Lemma 10.120.17
- Lemma 10.120.18
- Section 10.121: Orders of vanishing
- Section 10.122: Quasi-finite maps
- Section 10.123: Zariski's Main Theorem
- Section 10.124: Applications of Zariski's Main Theorem
- Section 10.125: Dimension of fibres
- Section 10.126: Algebras and modules of finite presentation
- Section 10.127: Colimits and maps of finite presentation
- Section 10.128: More flatness criteria
- Section 10.129: Openness of the flat locus
- Section 10.130: Openness of Cohen-Macaulay loci
-
Section 10.131: Differentials
- Definition 10.131.1
- Definition 10.131.2
- Lemma 10.131.3 slogan
-
Lemma 10.131.4
- Equation 10.131.4.1
- Equation 10.131.4.2
- Lemma 10.131.5
- Lemma 10.131.6
- Lemma 10.131.7
- Lemma 10.131.8
- Lemma 10.131.9
- Lemma 10.131.10
- Lemma 10.131.11
- Lemma 10.131.12
- Lemma 10.131.13
- Lemma 10.131.14
- Lemma 10.131.15
- Lemma 10.131.16
-
Section 10.132: The de Rham complex
- Equation 10.132.0.1
- Lemma 10.132.1
- Section 10.133: Finite order differential operators
-
Section 10.134: The naive cotangent complex
- Equation 10.134.0.1
- Equation 10.134.0.2
-
Definition 10.134.1
- Equation 10.134.1.1
- Lemma 10.134.2
- Lemma 10.134.3
- Lemma 10.134.4: Jacobi-Zariski sequence
- Remark 10.134.5
- Lemma 10.134.6
- Lemma 10.134.7
- Lemma 10.134.8: Flat base change
- Lemma 10.134.9
- Lemma 10.134.10
- Lemma 10.134.11
- Lemma 10.134.12 slogan
- Lemma 10.134.13
- Lemma 10.134.14
- Lemma 10.134.15
- Lemma 10.134.16
- Section 10.135: Local complete intersections
- Section 10.136: Syntomic morphisms
-
Section 10.137: Smooth ring maps
- Definition 10.137.1
- Lemma 10.137.2
- Lemma 10.137.3
- Lemma 10.137.4 slogan
- Lemma 10.137.5
- Definition 10.137.6
- Lemma 10.137.7
- Example 10.137.8
- Lemma 10.137.9
- Lemma 10.137.10
- Definition 10.137.11
- Lemma 10.137.12
- Lemma 10.137.13 slogan
- Lemma 10.137.14
- Lemma 10.137.15
- Lemma 10.137.16
- Lemma 10.137.17
- Lemma 10.137.18
- Lemma 10.137.19
- Lemma 10.137.20
-
Section 10.138: Formally smooth maps
- Definition 10.138.1
- Lemma 10.138.2
- Lemma 10.138.3
- Lemma 10.138.4
- Lemma 10.138.5
- Remark 10.138.6
- Lemma 10.138.7
- Proposition 10.138.8
- Lemma 10.138.9
- Lemma 10.138.10
- Lemma 10.138.11
-
Lemma 10.138.12
- Equation 10.138.12.1
- Proposition 10.138.13
- Lemma 10.138.14
- Lemma 10.138.15
- Lemma 10.138.16
- Lemma 10.138.17
- Section 10.139: Smoothness and differentials
- Section 10.140: Smooth algebras over fields
-
Section 10.141: Smooth ring maps in the Noetherian case
- Definition 10.141.1
-
Lemma 10.141.2
- Equation 10.141.2.1
- Section 10.142: Overview of results on smooth ring maps
- Section 10.143: Étale ring maps
- Section 10.144: Local structure of étale ring maps
- Section 10.145: Étale local structure of quasi-finite ring maps
- Section 10.146: Local homomorphisms
- Section 10.147: Integral closure and smooth base change
- Section 10.148: Formally unramified maps
- Section 10.149: Conormal modules and universal thickenings
- Section 10.150: Formally étale maps
- Section 10.151: Unramified ring maps
- Section 10.152: Local structure of unramified ring maps
- Section 10.153: Henselian local rings
- Section 10.154: Filtered colimits of étale ring maps
- Section 10.155: Henselization and strict henselization
- Section 10.156: Henselization and quasi-finite ring maps
- Section 10.157: Serre's criterion for normality
- Section 10.158: Formal smoothness of fields
- Section 10.159: Constructing flat ring maps
- Section 10.160: The Cohen structure theorem
- Section 10.161: Japanese rings
-
Section 10.162: Nagata rings
- Definition 10.162.1
- Lemma 10.162.2
- Lemma 10.162.3
- Lemma 10.162.4
- Lemma 10.162.5
- Lemma 10.162.6
- Lemma 10.162.7
- Lemma 10.162.8
- Definition 10.162.9
- Lemma 10.162.10
- Lemma 10.162.11
- Lemma 10.162.12
- Lemma 10.162.13
- Lemma 10.162.14
- Proposition 10.162.15: Nagata
- Proposition 10.162.16
- Example 10.162.17
- Lemma 10.162.18
- Section 10.163: Ascending properties
- Section 10.164: Descending properties
- Section 10.165: Geometrically normal algebras
- Section 10.166: Geometrically regular algebras
- Section 10.167: Geometrically Cohen-Macaulay algebras
- Section 10.168: Colimits and maps of finite presentation, II