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  • ..., the base change <math>X \times_Y Y' \to Y'</math> is a [[homeomorphism]] of topological spaces. ...f>EGA IV<sub>4</sub>, 18.12.11.</ref> In particular, a morphism of locally of finite type is a universal homeomorphism if and only if it is [[finite morp ...
    1 KB (143 words) - 01:05, 11 August 2019
  • ...definitions of an '''fpqc morphism''', both variations of faithfully flat morphisms. ...er it is more common to define an fpqc morphism <math>f: X \to Y</math> of schemes to be a [[faithfully flat morphism]] that satisfies the following equivalen ...
    2 KB (364 words) - 12:49, 28 February 2025
  • In [[algebraic geometry]], a morphism <math>f: X \to S</math> of [[scheme (mathematics)|scheme]]s is said to be '''locally acyclic''' if, ro [[Category:Morphisms of schemes]] ...
    653 bytes (85 words) - 07:32, 6 April 2023
  • ...er field, or the pullback of a family of varieties, or a fiber of a family of varieties. '''Base change''' is a closely related notion. ..., rather than simply studying [[algebraic curve]]s, one can study families of curves over any base scheme ''Y''. Indeed, the two approaches enrich each o ...
    8 KB (1,320 words) - 02:32, 9 January 2025
  • ...)|module]]. An <math>R</math>-algebra can be thought as a [[homomorphism]] of [[ring (mathematics)|rings]] <math>f\colon R \to A</math>, in this case <ma ...itely generated algebra#finite algebras vs algebras of finite type|algebra of finite type]]. ...
    2 KB (348 words) - 18:23, 6 February 2024
  • ...opology]]. The precise definition depends on one's formalism. But the idea of the definition itself is simple. The usual prime spectrum Spec enjoys the r ...Spét to be the right adjoint to the global section functor on the category of "spaces" with étale topology.<ref>{{harvnb|Lurie|loc=Remark 1.2.3.6.}}</ref ...
    2 KB (320 words) - 12:43, 3 March 2023
  • {{short description|Type of space in mathematics}} ...formal functions]], which is used to deduce theorems of interest for usual schemes. ...
    6 KB (1,042 words) - 02:35, 27 April 2024
  • ...X</math> in some category <math>\mathcal{C}</math>. There is a dual notion of undercategory, which is defined similarly. Let <math>\mathcal{C}</math> be a category and <math>X</math> a fixed object of <math>\mathcal{C}</math><ref>{{cite arXiv|last=Leinster|first=Tom|date=2016 ...
    5 KB (790 words) - 23:44, 16 October 2024
  • ...y sheaves]] <math>\pi_* F \to \pi_* G</math> is an isomorphism. A '''sheaf of spectra''' is then a fibrant/cofibrant object in that category. ....ku.dk/~jg/homotopical2008/goerss.lec2.pdf |first=Paul |last=Goerss |title=Schemes |work=TAG Lecture 2 |date=16 June 2008 }} ...
    932 bytes (137 words) - 11:04, 1 April 2021
  • ...aracteristic (algebra)|characteristic]] zero which have [[residue field]]s of characteristic [[prime number|prime]] ''p''. ...ive]] on ''K''°/''p'' where ''K''° denotes the [[ring (mathematics)|ring]] of power-bounded elements. ...
    5 KB (752 words) - 01:16, 30 March 2023
  • ...poid]] which is built on richer structures than sets, and a generalization of a [[group object]]s when the multiplication is only [[partial function|part ...ng finite [[pullback (category theory)|fiber product]]s consists of a pair of [[Object (category theory)|objects]] <math>R, U</math> together with five [ ...
    5 KB (874 words) - 19:53, 8 December 2024
  • ...>-algebra unless <math>A</math> = 0 or <math>n</math> = 0. Another example of a finite-type homomorphism that is not finite is <math>\mathbb{C}[t] \to \m {{expert needed|Mathematics |talk=distinction between finite type and locally of finite type|date=August 2023}} ...
    3 KB (502 words) - 05:57, 9 January 2025
  • In [[topology]], '''constructible sets''' are a class of subsets of a [[topological space]] that have a relatively "simple" structure. ...t the image of a constructible set is constructible for an important class of [[map (mathematics)|mappings]] ...
    10 KB (1,612 words) - 19:10, 6 December 2022
  • ...dsky]] to study the [[homology theory|homology]] of [[scheme (mathematics)|schemes]].<ref>{{citation | title = Homology of schemes ...
    11 KB (1,657 words) - 05:09, 16 November 2024
  • ...s generated by a [[regular sequence]] of length ''r''. A regular embedding of codimension one is precisely an [[effective Cartier divisor]]. ...-morphism, then ''i'' is a regular embedding. In particular, every section of a smooth morphism is a regular embedding.<ref>{{harvnb|Sernesi|2006|loc=D. ...
    8 KB (1,192 words) - 12:49, 5 May 2024
  • {{Short description|Type of ringed space}} ...af of commutative rings]] on ''X'' that is also a [[sheaf of modules|sheaf of <math>\mathcal{O}_X</math>-modules]]. It is [[quasi-coherent sheaf|quasi-co ...
    5 KB (820 words) - 17:03, 7 January 2025
  • ...e.g. an [[algebraic variety]]) can be obtained by '''gluing''' existing '''schemes''' through gluing maps. Suppose there is a (possibly infinite) family of schemes <math>\{ X_i \}_{i \in I}</math> and for pairs <math>i, j</math>, there are ...
    5 KB (830 words) - 16:03, 25 February 2025
  • ...open cover <math>\mathcal U_1</math>, and to let the triple intersections of this cover to be covered by yet another open cover <math>\mathcal U_2</math ...ath>. A '''hypercover''' is a semisimplicial object <math>U_\bullet</math> of this category such that <math>U_0 \to X</math> is an étale cover and such t ...
    4 KB (581 words) - 04:02, 17 January 2025
  • ...the latter subject, a [[Bohr topos]] is a ringed topos that plays the role of a quantum [[phase space]].<ref>{{Cite web|url=https://golem.ph.utexas.edu/c ...posé IV, Exercise 13.9), which is equivalent to saying that all the stalks of the structure ring object are local rings when there are [[enough points]]. ...
    5 KB (852 words) - 22:22, 14 January 2021
  • ...heory|Hodge-theoretic]] concepts. This idea has applications in the theory of [[moduli spaces]], in [[deformation theory]] and Fontaine's [[p-adic Hodge ...s could provide one which vanishes), and we only get a sheaf of submonoids of <math> \mathcal{O}_X </math>, multiplicatively. Remembering this additional ...
    5 KB (762 words) - 18:02, 28 July 2023
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