diff options
| author | Juan Marin Noguera <juan@mnpi.eu> | 2022-10-16 19:42:55 +0200 | 
|---|---|---|
| committer | Juan Marin Noguera <juan@mnpi.eu> | 2022-10-16 19:44:33 +0200 | 
| commit | 49f2ff845803fc3309a5b55b31c818c4b8e73337 (patch) | |
| tree | e3b0bbc546d8507dc37c08d09be0feb2e5a0b436 /ac/n1.lyx | |
| parent | adb0f628e2db4cf4d248241947fec08ff4b0b785 (diff) | |
AC tema 2
Diffstat (limited to 'ac/n1.lyx')
| -rw-r--r-- | ac/n1.lyx | 514 | 
1 files changed, 381 insertions, 133 deletions
| @@ -998,10 +998,6 @@ Dados anillos  \end_inset  . -\begin_inset Quotes crd -\end_inset - -  \end_layout  \begin_layout Standard @@ -2383,14 +2379,7 @@ Dados anillos  \end_inset  . -\begin_inset Quotes crd -\end_inset - -  -\begin_inset Quotes cld -\end_inset - -Si  + Si   \begin_inset Formula $e\in A$  \end_inset @@ -3823,6 +3812,55 @@ Sean  \end_layout  \begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +begin{exinfo} +\end_layout + +\end_inset + +Dados  +\begin_inset Formula $I,J,J'\trianglelefteq A$ +\end_inset + + con  +\begin_inset Formula $I\subseteq J,J'$ +\end_inset + +,  +\begin_inset Formula $\frac{J}{I}+\frac{J'}{I}=\frac{J+J'}{I}$ +\end_inset + +,  +\begin_inset Formula $\frac{J}{I}\cap\frac{J'}{I}=\frac{J\cap J'}{I}$ +\end_inset + + y  +\begin_inset Formula $\frac{J}{I}\frac{J'}{I}=\frac{JJ'}{I}$ +\end_inset + +. +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +end{exinfo} +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Standard  Hay tantos ideales de   \begin_inset Formula $\mathbb{Z}_{n}$  \end_inset @@ -4199,8 +4237,170 @@ comaximales  \end_inset  . + Propiedades: +\end_layout + +\begin_layout Enumerate +Si  +\begin_inset Formula $I\trianglelefteq A$ +\end_inset + + es comaximal con  +\begin_inset Formula $J_{1},\dots,J_{n}\trianglelefteq A$ +\end_inset + +, lo es con  +\begin_inset Formula $J_{1}\cdots J_{n}$ +\end_inset + + y con  +\begin_inset Formula $J_{1}\cap\dots\cap J_{n}$ +\end_inset + +. +\end_layout + +\begin_deeper +\begin_layout Standard +Basta verlo para el producto, pues la intersección es más grande. + Para  +\begin_inset Formula $n\in\{0,1\}$ +\end_inset + + es claro. + Para  +\begin_inset Formula $n=2$ +\end_inset + +, existen  +\begin_inset Formula $a,a'\in I$ +\end_inset + +,  +\begin_inset Formula $b\in J_{1}$ +\end_inset + + y  +\begin_inset Formula $b'\in J_{2}$ +\end_inset + + con  +\begin_inset Formula $1=a+b=a'+b'$ +\end_inset + +, luego  +\begin_inset Formula $1=aa'+ab'+ba'+bb'$ +\end_inset + + con  +\begin_inset Formula $bb'\in J_{1}J_{2}$ +\end_inset + + y el resto de sumandos en  +\begin_inset Formula $I$ +\end_inset + +. + Para  +\begin_inset Formula $n>2$ +\end_inset + + se hace inducción. +\end_layout + +\end_deeper +\begin_layout Enumerate +Si  +\begin_inset Formula $I_{1},\dots,I_{n}\trianglelefteq A$ +\end_inset + + son comaximales dos a dos,  +\begin_inset Formula $I_{1}\cdots I_{n}=I_{1}\cap\dots\cap I_{n}$ +\end_inset + +.  \end_layout +\begin_deeper +\begin_layout Standard +Para  +\begin_inset Formula $n\in\{0,1\}$ +\end_inset + + es claro. + Para  +\begin_inset Formula $n=2$ +\end_inset + +, sea  +\begin_inset Formula $x\in I_{1}\cap I_{2}$ +\end_inset + +, existen  +\begin_inset Formula $a\in I_{1}$ +\end_inset + + y  +\begin_inset Formula $b\in I_{2}$ +\end_inset + + con  +\begin_inset Formula $a+b=1$ +\end_inset + +, luego  +\begin_inset Formula $x=ax+bx$ +\end_inset + +, pero  +\begin_inset Formula $a\in I_{1}$ +\end_inset + + y  +\begin_inset Formula $x\in I_{2}$ +\end_inset + + y por tanto  +\begin_inset Formula $ax\in I_{1}I_{2}$ +\end_inset + +, y del mismo modo  +\begin_inset Formula $bx\in I_{1}I_{2}$ +\end_inset + +, luego  +\begin_inset Formula $I_{1}\cap I_{2}\subseteq I_{1}I_{2}$ +\end_inset + + y ya sabíamos que  +\begin_inset Formula $I_{1}I_{2}\subseteq I_{1}\cap I_{2}$ +\end_inset + +. + Para  +\begin_inset Formula $n>2$ +\end_inset + +, supuesto esto probado para  +\begin_inset Formula $n$ +\end_inset + + menor, por lo anterior  +\begin_inset Formula $I_{1}\cdots I_{n-1}=I_{1}\cap\dots\cap I_{n-1}$ +\end_inset + + es comaximal con  +\begin_inset Formula $I_{n}$ +\end_inset + + y basta usar el caso  +\begin_inset Formula $n=2$ +\end_inset + +. +\end_layout + +\end_deeper  \begin_layout Standard  \begin_inset ERT  status open @@ -4215,6 +4415,19 @@ begin{exinfo}  \end_inset +\end_layout + +\begin_layout Enumerate +\begin_inset Argument item:1 +status open + +\begin_layout Plain Layout +3. +\end_layout + +\end_inset + +  \begin_inset Formula $I,J\trianglelefteq A$  \end_inset @@ -4235,6 +4448,9 @@ begin{exinfo}  \end_inset   son comaximales. +\end_layout + +\begin_layout Standard  \begin_inset ERT  status open @@ -4320,75 +4536,20 @@ Para  \end_inset  . - Primero vemos que  -\begin_inset Formula $K_{1}$ -\end_inset - - es comaximal con  -\begin_inset Formula $K_{2}\cdots K_{n}$ -\end_inset - -. - Si  -\begin_inset Formula $n=2$ -\end_inset - - esto es claro. - Si  -\begin_inset Formula $n=3$ -\end_inset - -, existen  -\begin_inset Formula $a,a'\in K_{1}$ -\end_inset - -,  -\begin_inset Formula $b\in K_{2}$ -\end_inset - - y  -\begin_inset Formula $b'\in K_{3}$ -\end_inset - - con  -\begin_inset Formula $1=a+b=a'+b'$ -\end_inset - -, luego  -\begin_inset Formula $1=aa'+ab'+ba'+bb'$ -\end_inset - - con  -\begin_inset Formula $bb'\in K_{2}K_{3}$ + Al ser los  +\begin_inset Formula $K_{i}$  \end_inset - y el resto de sumandos en  + comaximales,   \begin_inset Formula $K_{1}$  \end_inset -. - Si  -\begin_inset Formula $n>3$ -\end_inset - - basta hacer inducción. - Al ser  + es comaximal con   \begin_inset Formula $K_{2}\cap\dots\cap K_{n}$  \end_inset - más grande que  -\begin_inset Formula $K_{2}\cdots K_{n}$ -\end_inset - -, también es comaximal con  -\begin_inset Formula $K_{1}$ -\end_inset -  . -\end_layout - -\begin_layout Standard -Sean ahora  + Sean ahora   \begin_inset Formula $a\in K_{1}$  \end_inset @@ -4479,69 +4640,11 @@ Sean ahora  \end_inset   es suprayectiva. -\end_layout - -\begin_layout Standard -Veamos ahora que  + Entonces   \begin_inset Formula $\ker\phi=K_{1}\cap\dots\cap K_{n}=K_{1}\cdots K_{n}$  \end_inset -. - Para  -\begin_inset Formula $n=2$ -\end_inset - -, sea  -\begin_inset Formula $x\in K_{1}\cap K_{2}$ -\end_inset - -, existen  -\begin_inset Formula $a\in K_{1}$ -\end_inset - - y  -\begin_inset Formula $b\in K_{2}$ -\end_inset - - con  -\begin_inset Formula $a+b=1$ -\end_inset - -, luego  -\begin_inset Formula $x=1x=ax+bx$ -\end_inset - -, pero como  -\begin_inset Formula $a\in K_{1}$ -\end_inset - - y  -\begin_inset Formula $x\in K_{2}$ -\end_inset - -,  -\begin_inset Formula $ax\in K_{1}K_{2}$ -\end_inset - -, y análogamente  -\begin_inset Formula $xb\in K_{1}K_{2}$ -\end_inset - -, luego  -\begin_inset Formula $x\in K_{1}K_{2}$ -\end_inset - - y  -\begin_inset Formula $K_{1}\cap K_{2}\subseteq K_{1}K_{2}$ -\end_inset - -, y la otra inclusión la sabemos. - Para  -\begin_inset Formula $n>2$ -\end_inset - - basta hacer inducción. - La última afirmación se debe al primer teorema de isomorfía. +, y para la última afirmación basta aplicar el primer teorema de isomorfía.  \end_layout  \end_deeper @@ -4929,6 +5032,7 @@ anillo local  \end_inset  . +   \end_layout  \begin_layout Standard @@ -4966,6 +5070,43 @@ Sean  \end_inset   es el único irreducible salvo asociados. +  +\end_layout + +\begin_layout Standard +Si  +\begin_inset Formula $(A,(p))$ +\end_inset + + es un anillo local con  +\begin_inset Formula $p\neq0$ +\end_inset + + y  +\begin_inset Formula $\bigcap_{n\in\mathbb{N}}(p)^{n}=0$ +\end_inset + +, cada  +\begin_inset Formula $a\in A\setminus0$ +\end_inset + + es de la forma  +\begin_inset Formula $up^{n}$ +\end_inset + + para ciertos  +\begin_inset Formula $u\in A^{*}$ +\end_inset + + y  +\begin_inset Formula $n\in\mathbb{N}$ +\end_inset + +, y en particular  +\begin_inset Formula $A$ +\end_inset + + es un DIP con un único irreducible salvo asociados.  \end_layout  \begin_layout Standard @@ -5038,6 +5179,66 @@ end{exinfo}  \end_layout +\begin_layout Standard +\begin_inset Formula $I\trianglelefteq A$ +\end_inset + + es  +\series bold +nilpotente +\series default + si existe  +\begin_inset Formula $n\in\mathbb{N}$ +\end_inset + + tal que  +\begin_inset Formula $I^{n}=0$ +\end_inset + +, donde  +\begin_inset Formula $I^{0}\coloneqq A$ +\end_inset + + y, para  +\begin_inset Formula $n>0$ +\end_inset + +,  +\begin_inset Formula $I^{n}\coloneqq II^{n-1}$ +\end_inset + +. +\end_layout + +\begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +begin{exinfo} +\end_layout + +\end_inset + +Todo ideal nil finitamente generado es nilpotente. +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +end{exinfo} +\end_layout + +\end_inset + + +\end_layout +  \begin_layout Section  Ideales primos  \end_layout @@ -5510,6 +5711,18 @@ status open  \end_layout  \begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +vspace{6pt} +\end_layout + +\end_inset +  Dados un homomorfismo   \begin_inset Formula $f:A\to B$  \end_inset @@ -5893,6 +6106,22 @@ radical  \end_layout  \begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +begin{samepage} +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Standard  Propiedades:  \end_layout @@ -5968,6 +6197,22 @@ Sea  \end_deeper  \begin_layout Standard +\begin_inset ERT +status open + +\begin_layout Plain Layout + + +\backslash +end{samepage} +\end_layout + +\end_inset + + +\end_layout + +\begin_layout Standard  Un   \series bold  subconjunto multiplicativo @@ -5981,9 +6226,12 @@ subconjunto multiplicativo  \end_inset   cerrado para el producto y que contiene al 1. +\end_layout + +\begin_layout Standard  \series bold - Lema de Krull: +Lema de Krull:  \series default   Sean   \begin_inset Formula $A$ | 
