diff --git a/algebra.tex b/algebra.tex index 4c03eff7..fe0bdc44 100644 --- a/algebra.tex +++ b/algebra.tex @@ -10559,7 +10559,7 @@ \section{Perfect fields} \begin{lemma} \label{lemma-perfect-reduced} Let $k$ be a perfect field. -Any reduced $k$ algebra is geometrically reduced over $k$. +Any reduced $k$-algebra is geometrically reduced over $k$. Let $R$, $S$ be $k$-algebras. Assume both $R$ and $S$ are reduced. Then the $k$-algebra $R \otimes_k S$ is reduced. @@ -13374,13 +13374,13 @@ \section{Proj of a graded ring} $$ \medskip\noindent -Let $S = \oplus_{d \geq 0} S_d$ be a graded ring. +Let $S = \bigoplus_{d \geq 0} S_d$ be a graded ring. Let $f\in S_d$ and assume that $d \geq 1$. We define $S_{(f)}$ to be the subring of $S_f$ consisting of elements of the form $r/f^n$ with $r$ homogeneous and $\deg(r) = nd$. If $M$ is a graded $S$-module, then we define the $S_{(f)}$-module $M_{(f)}$ as the -sub module of $M_f$ consisting of elements of +submodule of $M_f$ consisting of elements of the form $x/f^n$ with $x$ homogeneous of degree $nd$. \begin{lemma} @@ -13426,7 +13426,7 @@ \section{Proj of a graded ring} \begin{lemma}[Topology on Proj] \label{lemma-topology-proj} -Let $S = \oplus_{d \geq 0} S_d$ be a graded ring. +Let $S = \bigoplus_{d \geq 0} S_d$ be a graded ring. \begin{enumerate} \item The sets $D_{+}(f)$ are open in $\text{Proj}(S)$. \item We have $D_{+}(ff') = D_{+}(f) \cap D_{+}(f')$. @@ -15271,7 +15271,7 @@ \section{Associated primes} \begin{lemma} \label{lemma-one-equation-module} -Let $R$ is a Noetherian local ring, $M$ a finite $R$-module, and +Let $R$ be a Noetherian local ring, $M$ a finite $R$-module, and $f \in \mathfrak m$ an element of the maximal ideal of $R$. Then $$ \dim(\text{Supp}(M/fM)) \leq @@ -15496,7 +15496,7 @@ \section{Associated primes} \begin{lemma} \label{lemma-dim-not-zero-exists-nonzerodivisor-nonunit} -Let $k$ be a field. Let $S$ be a finite type $k$ algebra. +Let $k$ be a field. Let $S$ be a finite type $k$-algebra. If $\dim(S) > 0$, then there exists an element $f \in S$ which is a nonzerodivisor and a nonunit. \end{lemma} @@ -27812,7 +27812,7 @@ \section{Dimension of finite type algebras over fields} \begin{lemma} \label{lemma-disjoint-decomposition-CM-algebra} Let $k$ be a field. -Let $S$ be a finite type $k$ algebra. +Let $S$ be a finite type $k$-algebra. Assume that $S$ is Cohen-Macaulay. Then $\Spec(S) = \coprod T_d$ is a finite disjoint union of open and closed subsets $T_d$ with $T_d$ equidimensional @@ -27999,7 +27999,7 @@ \section{Noether normalization} \begin{lemma} \label{lemma-Noether-normalization-at-point} Let $k$ be a field. -Let $S$ be a finite type $k$ algebra and denote $X = \Spec(S)$. +Let $S$ be a finite type $k$-algebra and denote $X = \Spec(S)$. Let $\mathfrak q$ be a prime of $S$, and let $x \in X$ be the corresponding point. There exists a $g \in S$, $g \not \in \mathfrak q$ such that $\dim(S_g) = \dim_x(X) =: d$ and such that @@ -28120,7 +28120,7 @@ \section{Dimension of finite type algebras over fields, reprise} \begin{lemma} \label{lemma-dimension-prime-polynomial-ring} Let $k$ be a field. -Let $S$ be a finite type $k$ algebra which is an integral domain. +Let $S$ be a finite type $k$-algebra which is an integral domain. Let $K$ be the field of fractions of $S$. Let $r = \text{trdeg}(K/k)$ be the transcendence degree of $K$ over $k$. Then $\dim(S) = r$. Moreover, the local ring of $S$ at every maximal @@ -28164,7 +28164,7 @@ \section{Dimension of finite type algebras over fields, reprise} \begin{lemma} \label{lemma-dimension-at-a-point-finite-type-field} Let $k$ be a field. -Let $S$ be a finite type $k$ algebra. +Let $S$ be a finite type $k$-algebra. Let $X = \Spec(S)$. Let $\mathfrak p \subset S$ be a prime ideal, and let $x \in X$ be the corresponding point. @@ -28212,7 +28212,7 @@ \section{Dimension of finite type algebras over fields, reprise} \begin{lemma} \label{lemma-codimension} Let $k$ be a field. -Let $S' \to S$ be a surjection of finite type $k$ algebras. +Let $S' \to S$ be a surjection of finite type $k$-algebras. Let $\mathfrak p \subset S$ be a prime ideal, and let $\mathfrak p'$ be the corresponding prime ideal of $S'$. Let $X = \Spec(S)$, resp.\ $X' = \Spec(S')$, @@ -33550,7 +33550,7 @@ \section{Openness of Cohen-Macaulay loci} \begin{lemma} \label{lemma-generic-CM} -Let $k$ be a field. Let $S$ be a finite type $k$ algebra. +Let $k$ be a field. Let $S$ be a finite type $k$-algebra. The set of Cohen-Macaulay primes forms a dense open $U \subset \Spec(S)$. \end{lemma} diff --git a/constructions.tex b/constructions.tex index f097a4a0..061739fb 100644 --- a/constructions.tex +++ b/constructions.tex @@ -1630,7 +1630,7 @@ \section{Quasi-coherent sheaves on Proj} \begin{proof} To construct a morphism as displayed is the same as constructing -a $\mathcal{O}_X$-bilinear map +an $\mathcal{O}_X$-bilinear map $$ \widetilde M \times \widetilde N \longrightarrow @@ -2113,7 +2113,7 @@ \section{Functoriality of Proj} $$ A_f \otimes_{A_{(f)}} B_{(\psi(f))} \longrightarrow -B_{\psi(f)} +B_{\psi(f)}. $$ Condition (1) determines the images of all elements of $A$. Since $f$ is an invertible element which is mapped to $\psi(f)$ @@ -2402,7 +2402,7 @@ \section{Morphisms into Proj} (\ref{equation-multiply}) are isomorphisms. In particular we have $\mathcal{O}_{U_d}(nd) \cong \mathcal{O}_{U_d}(d)^{\otimes n}$. The graded ring map (\ref{equation-global-sections}) on global sections -combined with restriction to $U_d$ give a homomorphism of graded rings +combined with restriction to $U_d$ gives a homomorphism of graded rings \begin{equation} \label{equation-psi-d} \psi^d : S^{(d)} \longrightarrow \Gamma_*(U_d, \mathcal{O}_{U_d}(d)). @@ -2475,7 +2475,7 @@ \section{Morphisms into Proj} see Modules, Lemma \ref{modules-lemma-s-open}. We will denote the inverse of this map $x \mapsto x/s$, and similarly for powers of $\mathcal{L}$. Using this we -define a ring map $\psi_{(f)} : S_{(f)} \to \Gamma(Y_s, \mathcal{O})$ +define a ring map $\psi_{(f)} : S_{(f)} \to \Gamma(Y_s, \mathcal{O}_Y)$ by mapping the fraction $a/f^n$ to $\psi(a)/s^n$. By Schemes, Lemma \ref{schemes-lemma-morphism-into-affine} this corresponds to a morphism @@ -2511,7 +2511,7 @@ \section{Morphisms into Proj} \xymatrix{ \Gamma(Y_s, \mathcal{O}) \ar[r] & \Gamma(Y_{ss'}, \mathcal{O}) & -\Gamma(Y_{s, '} \mathcal{O}) \ar[l]\\ +\Gamma(Y_{s'}, \mathcal{O}) \ar[l]\\ S_{(f)} \ar[r] \ar[u]^{\psi_{(f)}} & S_{(ff')} \ar[u] & S_{(f')} \ar[l] \ar[u]^{\psi_{(f')}} @@ -2602,7 +2602,7 @@ \section{Morphisms into Proj} \end{lemma} \begin{proof} -This is a reformulation of Lemma \ref{lemma-converse-construction} +This is a reformulation of Lemma \ref{lemma-converse-construction}. \end{proof} \begin{lemma} @@ -3213,7 +3213,7 @@ \section{Invertible sheaves and morphisms into Proj} Let $\psi : A \to \Gamma_*(T, \mathcal{L})$ be a homomorphism of graded rings. Set $$ -U(\psi) = \bigcup\nolimits_{f \in A_{+}\text{ homogeneous}} T_{\psi(f)} +U(\psi) = \bigcup\nolimits_{f \in A_{+}\text{ homogeneous}} T_{\psi(f)}. $$ The morphism $\psi$ induces a canonical morphism of schemes $$ @@ -3443,6 +3443,7 @@ \section{Relative Proj via glueing} with $A = \mathcal{A}(U)$, $A' = \mathcal{A}(U')$ is the open immersion of Lemma \ref{lemma-proj-inclusion} above. \end{enumerate} +Moreover, $\underline{\text{Proj}}_S(\mathcal{A})$ is unique up to unique isomorphism over $S$. \end{lemma} \begin{proof} @@ -3450,6 +3451,7 @@ \section{Relative Proj via glueing} Lemmas \ref{lemma-relative-glueing}, \ref{lemma-proj-inclusion}, and \ref{lemma-transitive-proj}. +Uniqueness is stated in the last sentence of Lemma \ref{lemma-relative-glueing}. \end{proof} \begin{lemma} @@ -3656,7 +3658,7 @@ \section{Relative Proj as a functor} \medskip\noindent Let $(d, f : T \to S, \mathcal{L}, \psi)$ be a quadruple. -We may think of $\psi$ as a $\mathcal{O}_S$-module map +We may think of $\psi$ as an $\mathcal{O}_S$-module map $\mathcal{A}^{(d)} \to \bigoplus_{n \geq 0} f_*\mathcal{L}^{\otimes n}$. Since $\mathcal{A}^{(d)}$ is quasi-coherent this is the same thing as an $R$-linear homomorphism of graded rings diff --git a/derived.tex b/derived.tex index 523a61af..b0ad2810 100644 --- a/derived.tex +++ b/derived.tex @@ -7201,7 +7201,7 @@ \section{Cartan-Eilenberg resolutions} \medskip\noindent Computation of the first spectral sequence. We have -${}'E_1^{p, q} = H^q(L^{p, \bullet})$ in other words +${}'E_1^{p, q} = H^q(L^{p, \bullet})$, in other words $$ {}'E_1^{p, q} = H^q(F(I^{p, \bullet})) = R^qF(K^p) $$ @@ -7753,7 +7753,7 @@ \section{Right derived functors via resolution functors} \begin{lemma} \label{lemma-right-derived-functor} -Let $\mathcal{A}$ be an abelian category with enough injectives +Let $\mathcal{A}$ be an abelian category with enough injectives. Let $F : \mathcal{A} \to \mathcal{B}$ be an additive functor into an abelian category. Let $(i, j)$ be a resolution functor, see Definition \ref{definition-localization-functor}. @@ -9680,7 +9680,7 @@ \section{K-injective complexes} \end{lemma} \begin{proof} -Let $K^\bullet$ be an complex. Observe that the complex +Let $K^\bullet$ be a complex. Observe that the complex $$ C : \prod\nolimits_b \Hom(K^{-b}, I^{b - 1}) \to @@ -9964,7 +9964,7 @@ \section{Bounded cohomological dimension} consisting of right acyclic objects for $F$, \item for $E \in D(\mathcal{A})$ \begin{enumerate} -\item $H^i(RF(\tau_{\leq a}E) \to H^i(RF(E))$ is an isomorphism +\item $H^i(RF(\tau_{\leq a}E)) \to H^i(RF(E))$ is an isomorphism for $i \leq a$, \item $H^i(RF(E)) \to H^i(RF(\tau_{\geq b - n + 1}E))$ is an isomorphism for $i \geq b$, @@ -11079,7 +11079,7 @@ \section{Generators of triangulated categories} \item if $K_i \in \mathcal{D}$, $i = 1, \ldots, r$ with $T(K_i)$ for $i = 1, \ldots, r$, then $T(\bigoplus K_i)$, \item if $K \to L \to M \to K[1]$ is a distinguished triangle and -$T$ holds for two, then $T$ holds for the third object, +$T$ holds for two among $K$, $L$, $M$, then $T$ holds for the third object, \item if $T(K \oplus L)$ then $T(K)$ and $T(L)$, and \item $T(E[n])$ holds for all $n$. \end{enumerate} @@ -11230,11 +11230,11 @@ \section{Compact objects} of triangles $(E', C', C) \to (E', E'', E)$ and $(E', E'', E) \to (Y_{n - 1}, X_{n - 1}, X_n)$. The composition $C \to E \to X_n$ may not equal the given morphism $C \to X_n$, but -the compositions into $Y_{n - 1}$ are equal. Let $C \to X_{n - 1}$ +the compositions into $Y_{n - 1}[1]$ are equal. Let $C \to X_{n - 1}$ be a morphism that lifts the difference. By induction assumption we can factor this through a morphism $E''' \to X_{n - 1}$ with -$E''$ an object of $\langle \bigoplus_{i \in I'''} E_i \rangle$ -for some finite subset $I' \subset I$. Thus we see that we get +$E'''$ an object of $\langle \bigoplus_{i \in I'''} E_i \rangle$ +for some finite subset $I''' \subset I$. Thus we see that we get a solution on considering $E \oplus E''' \to X_n$ because $E \oplus E'''$ is an object of $\langle \bigoplus_{i \in I' \cup I'' \cup I'''} E_i \rangle$. diff --git a/homology.tex b/homology.tex index 4364a433..0492cf72 100644 --- a/homology.tex +++ b/homology.tex @@ -4584,7 +4584,7 @@ \section{Filtrations} \end{definition} \noindent -This also equivalent to requiring that $f^{-1}(F^iB) = F^iA + \Ker(f)$ +This is also equivalent to requiring that $f^{-1}(F^iB) = F^iA + \Ker(f)$ for all $i \in \mathbf{Z}$. We characterize strict morphisms as follows. @@ -6494,7 +6494,7 @@ \section{Spectral sequences: double complexes} weak convergence of the first spectral sequence if for all $n$ $$ \text{gr}_{F_I}(H^n(\text{Tot}(K^{\bullet, \bullet}))) = -\oplus_{p + q = n} {}'E_\infty^{p, q} +\bigoplus_{p + q = n} {}'E_\infty^{p, q} $$ via the canonical comparison of Lemma \ref{lemma-compute-cohomology-filtered-complex}. @@ -6502,7 +6502,7 @@ \section{Spectral sequences: double complexes} weakly converges if for all $n$ $$ \text{gr}_{F_{II}}(H^n(\text{Tot}(K^{\bullet, \bullet}))) = -\oplus_{p + q = n} {}''E_\infty^{p, q} +\bigoplus_{p + q = n} {}''E_\infty^{p, q} $$ via the canonical comparison of Lemma \ref{lemma-compute-cohomology-filtered-complex}. diff --git a/injectives.tex b/injectives.tex index 6370c550..60906b34 100644 --- a/injectives.tex +++ b/injectives.tex @@ -1755,7 +1755,7 @@ \section{K-injectives in Grothendieck categories} \end{lemma} \begin{proof} -Choose a functorial injective embeddings $i_M : M \to I(M)$, see +Choose functorial injective embeddings $i_M : M \to I(M)$, see Theorem \ref{theorem-injective-embedding-grothendieck}. For every complex $M^\bullet$ denote $J^\bullet(M^\bullet)$ the complex with terms $J^n(M^\bullet) = I(M^n) \oplus I(M^{n + 1})$ and differential @@ -1866,7 +1866,7 @@ \section{K-injectives in Grothendieck categories} Suppose that $M \subset U$ and $\varphi : M \to \mathbf{T}^n_\alpha(M^\bullet)$ is a morphism for some $n \in \mathbf{Z}$. By Proposition \ref{proposition-objects-are-small} -we see that $\varphi$ factor through +we see that $\varphi$ factors through $\mathbf{T}^n_{\alpha'}(M^\bullet)$ for some $\alpha' < \alpha$. In particular, by the construction of the functor $\mathbf{N}^\bullet(-)$ we see that $\varphi$ factors through @@ -1879,7 +1879,7 @@ \section{K-injectives in Grothendieck categories} complex such that $|K^n| \leq \kappa$. Then $K^\bullet \cong K_i^\bullet$ for some $i \in I$. Moreover, by Proposition \ref{proposition-objects-are-small} -once again we see that $w$ factor through +once again we see that $w$ factors through $\mathbf{T}^n_{\alpha'}(M^\bullet)$ for some $\alpha' < \alpha$. In particular, by the construction of the functor $\mathbf{M}^\bullet(-)$ we see that $w$ is homotopic to zero. @@ -2249,7 +2249,7 @@ \section{Additional remarks on Grothendieck abelian categories} $F^pK^\bullet$, $\text{gr}^pK^\bullet$. Let $M \in D(\mathcal{A})$. Using Lemma \ref{lemma-K-injective-embedding-filtration} we can construct a spectral sequence $(E_r, d_r)_{r \geq 1}$ -of bigraded objects of $\mathcal{A}$ with $d_r$ of bidgree +of bigraded objects of $\mathcal{A}$ with $d_r$ of bidegree $(r, -r + 1)$ and with $$ @@ -2318,7 +2318,7 @@ \section{Additional remarks on Grothendieck abelian categories} $M^\bullet/F^pM^\bullet$, $\text{gr}^pM^\bullet$. Dually to Remark \ref{remark-ext-into-filtered-complex} we can construct a spectral sequence $(E_r, d_r)_{r \geq 1}$ -of bigraded objects of $\mathcal{A}$ with $d_r$ of bidgree +of bigraded objects of $\mathcal{A}$ with $d_r$ of bidegree $(r, -r + 1)$ and with $$ diff --git a/modules.tex b/modules.tex index fc041cab..b7c37358 100644 --- a/modules.tex +++ b/modules.tex @@ -4289,8 +4289,8 @@ \section{Invertible modules} (although this is ambiguous if $\mathcal{F}$ is invertible). The multiplication of $\Gamma_*(\mathcal{L})$ on $\Gamma_*(\mathcal{F})$ is defined using the isomorphisms -above. If $\gamma : \mathcal{F} \to \mathcal{G}$ is a $\mathcal{O}_X$-module -map, then we get an $\Gamma_*(\mathcal{L})$-module homomorphism +above. If $\gamma : \mathcal{F} \to \mathcal{G}$ is an $\mathcal{O}_X$-module +map, then we get a $\Gamma_*(\mathcal{L})$-module homomorphism $\gamma : \Gamma_*(\mathcal{F}) \to \Gamma_*(\mathcal{G})$. If $\alpha : \mathcal{L} \to \mathcal{N}$ is an $\mathcal{O}_X$-module map between invertible $\mathcal{O}_X$-modules, then we obtain diff --git a/more-algebra.tex b/more-algebra.tex index ac3c99b3..9e222a65 100644 --- a/more-algebra.tex +++ b/more-algebra.tex @@ -23505,7 +23505,7 @@ \section{Rlim of modules} \begin{proof} The proof is exactly the same as the proof of Lemma \ref{lemma-distinguished-triangle-Rlim} -using Lemma \ref{lemma-compute-Rlim-modules} in stead of +using Lemma \ref{lemma-compute-Rlim-modules} instead of Lemma \ref{lemma-compute-Rlim}. \end{proof} diff --git a/more-etale.tex b/more-etale.tex index 1e9b69b2..4537bfa3 100644 --- a/more-etale.tex +++ b/more-etale.tex @@ -145,7 +145,7 @@ \section{Sections with compact support} \label{section-compact-support} \noindent -A reference for this section is \cite[Exposee XVII, Section 6]{SGA4}. +A reference for this section is \cite[Exposé XVII, Section 6]{SGA4}. Let $f : X \to Y$ be a morphism of schemes which is separated and locally of finite type. In this section we define a functor $f_! : \textit{Ab}(X_\etale) \to \textit{Ab}(Y_\etale)$