The Stacks project

5 Topics in Geometry

  • Chapter 81: Chow Groups of Spaces
    • Section 81.1: Introduction
    • Section 81.2: Setup
    • Section 81.3: Cycles
    • Section 81.4: Multiplicities
    • Section 81.5: Cycle associated to a closed subspace
    • Section 81.6: Cycle associated to a coherent sheaf
    • Section 81.7: Preparation for proper pushforward
    • Section 81.8: Proper pushforward
    • Section 81.9: Preparation for flat pullback
    • Section 81.10: Flat pullback
    • Section 81.11: Push and pull
    • Section 81.12: Preparation for principal divisors
    • Section 81.13: Principal divisors
    • Section 81.14: Principal divisors and pushforward
    • Section 81.15: Rational equivalence
    • Section 81.16: Rational equivalence and push and pull
    • Section 81.17: The divisor associated to an invertible sheaf
    • Section 81.18: Intersecting with an invertible sheaf
    • Section 81.19: Intersecting with an invertible sheaf and push and pull
    • Section 81.20: The key formula
    • Section 81.21: Intersecting with an invertible sheaf and rational equivalence
    • Section 81.22: Intersecting with effective Cartier divisors
    • Section 81.23: Gysin homomorphisms
    • Section 81.24: Relative effective Cartier divisors
    • Section 81.25: Affine bundles
    • Section 81.26: Bivariant intersection theory
    • Section 81.27: Projective space bundle formula
    • Section 81.28: The Chern classes of a vector bundle
    • Section 81.29: Polynomial relations among Chern classes
    • Section 81.30: Additivity of Chern classes
    • Section 81.31: The splitting principle
    • Section 81.32: Degrees of zero cycles
  • Chapter 82: Quotients of Groupoids
    • Section 82.1: Introduction
    • Section 82.2: Conventions and notation
    • Section 82.3: Invariant morphisms
    • Section 82.4: Categorical quotients
    • Section 82.5: Quotients as orbit spaces
    • Section 82.6: Coarse quotients
    • Section 82.7: Topological properties
    • Section 82.8: Invariant functions
    • Section 82.9: Good quotients
    • Section 82.10: Geometric quotients
  • Chapter 83: More on Cohomology of Spaces
    • Section 83.1: Introduction
    • Section 83.2: Conventions
    • Section 83.3: Transporting results from schemes
    • Section 83.4: Proper base change
    • Section 83.5: Comparing big and small topoi
    • Section 83.6: Comparing fppf and étale topologies
    • Section 83.7: Comparing fppf and étale topologies: modules
    • Section 83.8: Comparing ph and étale topologies
  • Chapter 84: Simplicial Spaces
    • Section 84.1: Introduction
    • Section 84.2: Simplicial topological spaces
    • Section 84.3: Simplicial sites and topoi
    • Section 84.4: Augmentations of simplicial sites
    • Section 84.5: Morphisms of simplicial sites
    • Section 84.6: Ringed simplicial sites
    • Section 84.7: Morphisms of ringed simplicial sites
    • Section 84.8: Cohomology on simplicial sites
    • Section 84.9: Cohomology and augmentations of simplicial sites
    • Section 84.10: Cohomology on ringed simplicial sites
    • Section 84.11: Cohomology and augmentations of ringed simplicial sites
    • Section 84.12: Cartesian sheaves and modules
    • Section 84.13: Simplicial systems of the derived category
    • Section 84.14: Simplicial systems of the derived category: modules
    • Section 84.15: The site associated to a semi-representable object
    • Section 84.16: The site associate to a simplicial semi-representable object
    • Section 84.17: Cohomological descent for hypercoverings
    • Section 84.18: Cohomological descent for hypercoverings: modules
    • Section 84.19: Cohomological descent for hypercoverings of an object
    • Section 84.20: Cohomological descent for hypercoverings of an object: modules
    • Section 84.21: Hypercovering by a simplicial object of the site
    • Section 84.22: Hypercovering by a simplicial object of the site: modules
    • Section 84.23: Unbounded cohomological descent for hypercoverings
    • Section 84.24: Glueing complexes
    • Section 84.25: Proper hypercoverings in topology
    • Section 84.26: Simplicial schemes
    • Section 84.27: Descent in terms of simplicial schemes
    • Section 84.28: Quasi-coherent modules on simplicial schemes
    • Section 84.29: Groupoids and simplicial schemes
    • Section 84.30: Descent data give equivalence relations
    • Section 84.31: An example case
    • Section 84.32: Simplicial algebraic spaces
    • Section 84.33: Fppf hypercoverings of algebraic spaces
    • Section 84.34: Fppf hypercoverings of algebraic spaces: modules
    • Section 84.35: Fppf descent of complexes
    • Section 84.36: Proper hypercoverings of algebraic spaces
  • Chapter 85: Duality for Spaces
    • Section 85.1: Introduction
    • Section 85.2: Dualizing complexes on algebraic spaces
    • Section 85.3: Right adjoint of pushforward
    • Section 85.4: Right adjoint of pushforward and base change, I
    • Section 85.5: Right adjoint of pushforward and base change, II
    • Section 85.6: Right adjoint of pushforward and trace maps
    • Section 85.7: Right adjoint of pushforward and pullback
    • Section 85.8: Right adjoint of pushforward for proper flat morphisms
    • Section 85.9: Relative dualizing complexes for proper flat morphisms
    • Section 85.10: Comparison with the case of schemes
  • Chapter 86: Formal Algebraic Spaces
    • Section 86.1: Introduction
    • Section 86.2: Formal schemes à la EGA
    • Section 86.3: Conventions and notation
    • Section 86.4: Topological rings and modules
    • Section 86.5: Taut ring maps
    • Section 86.6: Adic ring maps
    • Section 86.7: Weakly adic rings
    • Section 86.8: Descending properties
    • Section 86.9: Affine formal algebraic spaces
    • Section 86.10: Countably indexed affine formal algebraic spaces
    • Section 86.11: Formal algebraic spaces
    • Section 86.12: The reduction
    • Section 86.13: Colimits of algebraic spaces along thickenings
    • Section 86.14: Completion along a closed subset
    • Section 86.15: Fibre products
    • Section 86.16: Separation axioms for formal algebraic spaces
    • Section 86.17: Quasi-compact formal algebraic spaces
    • Section 86.18: Quasi-compact and quasi-separated formal algebraic spaces
    • Section 86.19: Morphisms representable by algebraic spaces
    • Section 86.20: Types of formal algebraic spaces
    • Section 86.21: Morphisms and continuous ring maps
    • Section 86.22: Taut ring maps and representability by algebraic spaces
    • Section 86.23: Adic morphisms
    • Section 86.24: Morphisms of finite type
    • Section 86.25: Surjective morphisms
    • Section 86.26: Monomorphisms
    • Section 86.27: Closed immersions
    • Section 86.28: Restricted power series
    • Section 86.29: Algebras topologically of finite type
    • Section 86.30: Separation axioms for morphisms
    • Section 86.31: Proper morphisms
    • Section 86.32: Formal algebraic spaces and fpqc coverings
    • Section 86.33: Maps out of affine formal schemes
    • Section 86.34: The small étale site of a formal algebraic space
    • Section 86.35: The structure sheaf
    • Section 86.36: Colimits of formal algebraic spaces
    • Section 86.37: Recompletion
    • Section 86.38: Completion along a closed subspace
  • Chapter 87: Algebraization of Formal Spaces
    • Section 87.1: Introduction
    • Section 87.2: Two categories
    • Section 87.3: A naive cotangent complex
    • Section 87.4: Rig-smooth algebras
    • Section 87.5: Deformations of ring homomorphisms
    • Section 87.6: Algebraization of rig-smooth algebras over G-rings
    • Section 87.7: Algebraization of rig-smooth algebras
    • Section 87.8: Rig-étale algebras
    • Section 87.9: A pushout argument
    • Section 87.10: Algebraization of rig-étale algebras
    • Section 87.11: Finite type morphisms
    • Section 87.12: Finite type on reductions
    • Section 87.13: Flat morphisms
    • Section 87.14: Rig-closed points
    • Section 87.15: Rig-flat homomorphisms
    • Section 87.16: Rig-flat morphisms
    • Section 87.17: Rig-smooth homomorphisms
    • Section 87.18: Rig-smooth morphisms
    • Section 87.19: Rig-étale homomorphisms
    • Section 87.20: Rig-étale morphisms
    • Section 87.21: Rig-surjective morphisms
    • Section 87.22: Formal algebraic spaces over cdvrs
    • Section 87.23: The completion functor
    • Section 87.24: Formal modifications
    • Section 87.25: Completions and morphisms, I
    • Section 87.26: Rig glueing of morphisms
    • Section 87.27: Algebraization of rig-étale morphisms
    • Section 87.28: Completions and morphisms, II
    • Section 87.29: Artin's theorem on dilatations
    • Section 87.30: Application to modifications
  • Chapter 88: Resolution of Surfaces Revisited
    • Section 88.1: Introduction
    • Section 88.2: Modifications
    • Section 88.3: Strategy
    • Section 88.4: Dominating by quadratic transformations
    • Section 88.5: Dominating by normalized blowups
    • Section 88.6: Base change to the completion
    • Section 88.7: Implied properties
    • Section 88.8: Resolution
    • Section 88.9: Examples