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24 changes: 12 additions & 12 deletions algebra.tex
Original file line number Diff line number Diff line change
Expand Up @@ -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.
Expand Down Expand Up @@ -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}
Expand Down Expand Up @@ -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 $D_{+}(ff') = D_{+}(f) \cap D_{+}(f')$.
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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}
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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.
Expand Down Expand Up @@ -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.\ $X' = \Spec(S')$,
Expand Down Expand Up @@ -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}
Expand Down
18 changes: 10 additions & 8 deletions constructions.tex
Original file line number Diff line number Diff line change
Expand Up @@ -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
$$
\widetilde M \times \widetilde N
\longrightarrow
Expand Down Expand Up @@ -2113,7 +2113,7 @@ \section{Functoriality of Proj}
$$
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 $\psi(f)$
Expand Down Expand Up @@ -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)).
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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')}}
Expand Down Expand Up @@ -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}
Expand Down Expand Up @@ -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
$$
Expand Down Expand Up @@ -3443,13 +3443,15 @@ \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}
Follows immediately from
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}
Expand Down Expand Up @@ -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
Expand Down
16 changes: 8 additions & 8 deletions derived.tex
Original file line number Diff line number Diff line change
Expand Up @@ -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
$$
{}'E_1^{p, q} = H^q(F(I^{p, \bullet})) = R^qF(K^p)
$$
Expand Down Expand Up @@ -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}.
Expand Down Expand Up @@ -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
Expand Down Expand Up @@ -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 $i \geq b$,
Expand Down Expand Up @@ -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}
Expand Down Expand Up @@ -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
$\langle \bigoplus_{i \in I' \cup I'' \cup I'''} E_i \rangle$.
Expand Down
6 changes: 3 additions & 3 deletions homology.tex
Original file line number Diff line number Diff line change
Expand Up @@ -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.

Expand Down Expand Up @@ -6494,15 +6494,15 @@ \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}.
Similarly the second spectral sequence $({}''E_r, {}''d_r)_{r \geq 0}$
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}.
Expand Down
10 changes: 5 additions & 5 deletions injectives.tex
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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
Expand All @@ -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.
Expand Down Expand Up @@ -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
$$
Expand Down Expand Up @@ -2318,7 +2318,7 @@ \section{Additional remarks on Grothendieck abelian categories}
$M^\bullet/F^pM^\bullet$, $\text{gr}^pM^\bullet$.
Dually to Remark \ref{remark-ext-into-filtered-complex}
we can construct a spectral sequence $(E_r, d_r)_{r \geq 1}$
of bigraded objects of $\mathcal{A}$ with $d_r$ of bidgree
of bigraded objects of $\mathcal{A}$ with $d_r$ of bidegree
$(r, -r + 1)$ and
with
$$
Expand Down
4 changes: 2 additions & 2 deletions modules.tex
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down
2 changes: 1 addition & 1 deletion more-algebra.tex
Original file line number Diff line number Diff line change
Expand Up @@ -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}

Expand Down
2 changes: 1 addition & 1 deletion more-etale.tex
Original file line number Diff line number Diff line change
Expand Up @@ -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
$f_! : \textit{Ab}(X_\etale) \to \textit{Ab}(Y_\etale)$
Expand Down