#LyX 2.3 created this file. For more info see http://www.lyx.org/ \lyxformat 544 \begin_document \begin_header \save_transient_properties true \origin unavailable \textclass book \begin_preamble \input{../defs} \end_preamble \use_default_options true \maintain_unincluded_children false \language spanish \language_package default \inputencoding auto \fontencoding global \font_roman "default" "default" \font_sans "default" "default" \font_typewriter "default" "default" \font_math "auto" "auto" \font_default_family default \use_non_tex_fonts false \font_sc false \font_osf false \font_sf_scale 100 100 \font_tt_scale 100 100 \use_microtype false \use_dash_ligatures true \graphics default \default_output_format default \output_sync 0 \bibtex_command default \index_command default \paperfontsize default \spacing single \use_hyperref false \papersize default \use_geometry false \use_package amsmath 1 \use_package amssymb 1 \use_package cancel 1 \use_package esint 1 \use_package mathdots 1 \use_package mathtools 1 \use_package mhchem 1 \use_package stackrel 1 \use_package stmaryrd 1 \use_package undertilde 1 \cite_engine basic \cite_engine_type default \biblio_style plain \use_bibtopic false \use_indices false \paperorientation portrait \suppress_date false \justification true \use_refstyle 1 \use_minted 0 \index Index \shortcut idx \color #008000 \end_index \secnumdepth 3 \tocdepth 3 \paragraph_separation indent \paragraph_indentation default \is_math_indent 0 \math_numbering_side default \quotes_style french \dynamic_quotes 0 \papercolumns 1 \papersides 1 \paperpagestyle default \tracking_changes false \output_changes false \html_math_output 0 \html_css_as_file 0 \html_be_strict false \end_header \begin_body \begin_layout Standard Un \series bold alfabeto \series default \begin_inset Formula $\Sigma$ \end_inset es un conjunto finito de \series bold símbolos \series default . Una \series bold cadena \series default en \begin_inset Formula $\Sigma$ \end_inset es un elemento de \begin_inset Formula $\Sigma^{*}\coloneqq\bigcup_{n\in\mathbb{N}}\Sigma^{n}$ \end_inset , que solemos escribir como \begin_inset Formula $u_{1}\cdots u_{n}\coloneqq(u_{1},\dots,u_{n})$ \end_inset . Dadas dos cadenas \begin_inset Formula $u,v\in\Sigma^{*}$ \end_inset , llamamos \series bold concatenación \series default de \begin_inset Formula $u$ \end_inset y \begin_inset Formula $v$ \end_inset a \begin_inset Formula $u\cdot v\coloneqq u_{1}\cdots u_{|u|}v_{1}\cdots v_{|v|}$ \end_inset . \begin_inset Formula $\Sigma^{*}$ \end_inset es un monoide con la concatenación de cadenas, y llamamos \begin_inset Formula $\epsilon$ \end_inset a su elemento neutro. Dada \begin_inset Formula $u=u_{1}\cdots u_{n}\in\Sigma^{*}$ \end_inset , llamamos \begin_inset Formula $u^{\text{R}}\coloneqq u_{n}u_{n-1}\cdots u_{1}$ \end_inset . \end_layout \begin_layout Standard Un \series bold lenguaje \series default sobre \begin_inset Formula $\Sigma$ \end_inset es un \begin_inset Formula $L\in{\cal U}_{\Sigma}\coloneqq{\cal P}(\Sigma^{*})$ \end_inset . La \series bold concatenación \series default de dos lenguajes \begin_inset Formula $L_{1},L_{2}\subseteq\Sigma^{*}$ \end_inset es \begin_inset Formula $L_{1}\cdot L_{2}\coloneqq\{uv\}_{u\in L_{1},v\in L_{2}}$ \end_inset . \begin_inset Formula ${\cal P}(\Sigma^{*})$ \end_inset es un monoide con la concatenación de lenguajes. La \series bold clausura \series default o \series bold \emph on \lang english Kleene star \series default \emph default \lang spanish de un lenguaje \begin_inset Formula $L$ \end_inset es \begin_inset Formula $L^{*}\coloneqq\bigcup_{n\in\mathbb{N}}L^{n}$ \end_inset . \end_layout \begin_layout Section Autómatas finitos \end_layout \begin_layout Standard Un \series bold autómata finito determinista \series default ( \series bold DFA \series default , \emph on \lang english Deterministic Finite Automaton \emph default \lang spanish ) es una tupla \begin_inset Formula $(Q,\Sigma,\delta,q_{0},F)$ \end_inset formada por un conjunto finito de \series bold estados \series default \begin_inset Formula $Q$ \end_inset , un alfabeto \begin_inset Formula $\Sigma$ \end_inset , una \series bold función de transición \series default \begin_inset Formula $\delta:Q\times\Sigma\to Q$ \end_inset , un \series bold estado inicial \series default \begin_inset Formula $q_{0}\in Q$ \end_inset y un conjunto de \series bold estados finales \series default o \series bold de aceptación \series default \begin_inset Formula $F\subseteq Q$ \end_inset . \end_layout \begin_layout Standard Un \series bold autómata finito no determinista \series default ( \series bold NFA \series default , \emph on \lang english Nondeterministic Finite Automaton \emph default \lang spanish ) es una tupla \begin_inset Formula $(Q,\Sigma,\delta,q_{0},F)$ \end_inset formada por un conjunto finito de \series bold estados \series default \begin_inset Formula $Q$ \end_inset , un alfabeto \begin_inset Formula $\Sigma$ \end_inset , una \series bold función de transición \series default \begin_inset Formula $\delta:Q\times(\Sigma_{\epsilon}\coloneqq\Sigma^{1}\cup\{\epsilon\})\to{\cal P}(Q)$ \end_inset , un \series bold estado inicial \series default \begin_inset Formula $q_{0}\in Q$ \end_inset y un conjunto de \series bold estados finales \series default o \series bold de aceptación \series default \begin_inset Formula $F\subseteq Q$ \end_inset . \end_layout \begin_layout Standard Un NFA \begin_inset Formula $(Q,\Sigma,\delta,q_{0},F)$ \end_inset \series bold acepta \series default una cadena \begin_inset Formula $w\in\Sigma^{*}$ \end_inset si existen \begin_inset Formula $m\in\mathbb{N}$ \end_inset , \begin_inset Formula $(y_{1},\dots,y_{m})\in(\Sigma_{\epsilon})^{m}$ \end_inset y \begin_inset Formula $(r_{0},\dots,r_{m})\in Q^{m+1}$ \end_inset tales que \begin_inset Formula $r_{0}=q_{0}$ \end_inset , \begin_inset Formula $r_{m}\in F$ \end_inset y, para \begin_inset Formula $i\in\{0,\dots,m-1\}$ \end_inset , \begin_inset Formula $r_{i+1}\in\delta(r_{i},y_{i+1})$ \end_inset . Un DFA \begin_inset Formula $(Q,\Sigma,\delta,q_{0},F)$ \end_inset \series bold acepta \series default una cadena \begin_inset Formula $w\in\Sigma^{*}$ \end_inset si el NFA \begin_inset Formula $(Q,\Sigma,\delta',q_{0},F)$ \end_inset lo acepta, donde \begin_inset Formula $\delta'$ \end_inset viene dado por \begin_inset Formula $\delta'(q,a)\coloneqq\{\delta(q,a)\}$ \end_inset y \begin_inset Formula $\delta'(q,\emptyset)\coloneqq\emptyset$ \end_inset para \begin_inset Formula $q\in Q$ \end_inset y \begin_inset Formula $a\in\Sigma$ \end_inset . El \series bold lenguaje aceptado \series default por un DFA o NFA \begin_inset Formula ${\cal A}$ \end_inset , \begin_inset Formula $L({\cal A})$ \end_inset , es el conjunto de cadenas aceptadas por \begin_inset Formula ${\cal A}$ \end_inset . \end_layout \begin_layout Standard Llamamos \begin_inset Formula ${\cal L}_{\text{DFA}}$ \end_inset a la clase de lenguajes aceptados por algún DFA, y \begin_inset Formula ${\cal L}_{\text{NFA}}$ \end_inset a la de lenguajes aceptados por algún NFA. Como \series bold teorema \series default , \begin_inset Formula ${\cal L}_{\text{DFA}}={\cal L}_{\text{NFA}}$ \end_inset . \begin_inset Note Comment status open \begin_layout Itemize \begin_inset Argument item:1 status open \begin_layout Plain Layout \begin_inset Formula $\subseteq]$ \end_inset \end_layout \end_inset Trivial. \end_layout \begin_layout Itemize \begin_inset Argument item:1 status open \begin_layout Plain Layout \begin_inset Formula $\supseteq]$ \end_inset \end_layout \end_inset Sean \begin_inset Formula ${\cal A}\coloneqq(Q,\Sigma,\delta,q_{0},F)$ \end_inset un NFA, \begin_inset Formula $Q'\coloneqq{\cal P}(Q)$ \end_inset y \begin_inset Formula $F'\coloneqq\{r\in Q'\mid r\cap F\neq\emptyset\}$ \end_inset . Para \begin_inset Formula $r\in Q'$ \end_inset , decimos que \begin_inset Formula $q\in Q$ \end_inset es alcanzable desde \begin_inset Formula $r$ \end_inset si existen \begin_inset Formula $m\in\mathbb{N}$ \end_inset y una secuencia \begin_inset Formula $(q_{0},\dots,q_{m})$ \end_inset de elementos de \begin_inset Formula $Q$ \end_inset tal que \begin_inset Formula $q_{0}\in r$ \end_inset , \begin_inset Formula $q_{m}=q$ \end_inset y, para \begin_inset Formula $i\in\{0,\dots,m-1\}$ \end_inset , \begin_inset Formula $q_{i+1}\in\delta(q_{i},\varepsilon)$ \end_inset . Llamamos entonces \begin_inset Formula $E(r)$ \end_inset al conjunto de elementos de \begin_inset Formula $Q$ \end_inset alcanzables desde \begin_inset Formula $r$ \end_inset , con lo que \begin_inset Formula $r\subseteq E(r)$ \end_inset , y definimos \begin_inset Formula $\delta':Q'\times\Sigma\to Q'$ \end_inset como \begin_inset Formula \[ \delta'(r,a)\coloneqq\bigcup_{q\in r}E(\delta(q,a)). \] \end_inset Dado el DFA \begin_inset Formula ${\cal A}'\coloneqq(Q',\Sigma,\delta',E(q_{0}),F')$ \end_inset , queremos ver \begin_inset Formula $L({\cal A}')=L({\cal A})$ \end_inset . Llamamos \begin_inset Formula ${\cal A}_{q}$ \end_inset a un NFA como \begin_inset Formula ${\cal A}$ \end_inset pero con estado inicial \begin_inset Formula $q$ \end_inset , y \begin_inset Formula ${\cal A}'_{r}$ \end_inset a un DFA como \begin_inset Formula ${\cal A}'$ \end_inset pero con estado inicial \begin_inset Formula $r$ \end_inset . \end_layout \begin_deeper \begin_layout Itemize \begin_inset Argument item:1 status open \begin_layout Plain Layout \begin_inset Formula $\subseteq]$ \end_inset \end_layout \end_inset Sea \begin_inset Formula $w=w_{1}\cdots w_{n}\in L({\cal A}')$ \end_inset , existen \begin_inset Formula $r_{0},\dots,r_{n}\in Q'$ \end_inset con \begin_inset Formula $\delta'(r_{i},w_{i})=r_{i+1}$ \end_inset para cada \begin_inset Formula $i$ \end_inset , \begin_inset Formula $r_{0}=E(q_{0})$ \end_inset y \begin_inset Formula $r_{n}\in F'$ \end_inset , y queremos probar que para cada \begin_inset Formula $i$ \end_inset existe un \begin_inset Formula $q_{i}\in r_{i}$ \end_inset tal que \begin_inset Formula $w_{i+1}\cdots w_{n}\in L({\cal A}_{q_{i}})$ \end_inset . \end_layout \begin_deeper \begin_layout Plain Layout Para \begin_inset Formula $i=n$ \end_inset , tomamos \begin_inset Formula $q_{n}\in r_{n}\cap F$ \end_inset y \begin_inset Formula $\lambda\in L({\cal A}_{q_{n}})$ \end_inset . Probado esto para un \begin_inset Formula $i\geq1$ \end_inset , para \begin_inset Formula $i-1$ \end_inset , \begin_inset Formula $q_{i}\in\delta'(r_{i-1},w_{i})$ \end_inset y por tanto existe un \begin_inset Formula $q_{i-1}\in r_{i-1}$ \end_inset tal que \begin_inset Formula $q_{i}\in E(\delta(q_{i-1},w_{i}))$ \end_inset . Así, existen \begin_inset Formula $s_{0},\dots,s_{l}\in Q$ \end_inset con \begin_inset Formula $s_{0}\in\delta(q_{i-1},w_{i})$ \end_inset , \begin_inset Formula $s_{l}=q_{i}$ \end_inset y cada \begin_inset Formula $s_{j+1}\in\delta(s_{j},\epsilon)$ \end_inset , pero por hipótesis de inducción, existen \begin_inset Formula $a_{1},\dots,a_{k}\in\Sigma_{\epsilon}$ \end_inset y \begin_inset Formula $p_{0},\dots,p_{k}\in Q$ \end_inset con \begin_inset Formula $a_{1}\cdots a_{k}=w_{i+1}\cdots w_{n}$ \end_inset , \begin_inset Formula $p_{0}=q_{i}$ \end_inset , \begin_inset Formula $p_{k}\in F$ \end_inset y cada \begin_inset Formula $p_{k+1}\in\delta(p_{k},a_{k+1})$ \end_inset , de modo que las secuencias \begin_inset Formula $q_{i-1},s_{0},\dots,s_{l}=p_{0},\dots,p_{k}$ \end_inset y \begin_inset Formula $w_{i},\overbrace{\epsilon,\dots,\epsilon}^{l},a_{1},\dots,a_{k}$ \end_inset prueban que \begin_inset Formula $w_{i}\cdots w_{n}\in L({\cal A}_{q_{i-1}})$ \end_inset . Entonces \begin_inset Formula $w\in L({\cal A}_{q_{0}})$ \end_inset y, añadiendo transiciones \begin_inset Formula $\epsilon$ \end_inset como antes del estado inicial al \begin_inset Formula $q_{0}$ \end_inset obtenido, vemos que \begin_inset Formula $w\in L({\cal A})$ \end_inset . \end_layout \end_deeper \begin_layout Itemize \begin_inset Argument item:1 status open \begin_layout Plain Layout \begin_inset Formula $\supseteq]$ \end_inset \end_layout \end_inset Sea \begin_inset Formula $w=w_{1}\cdots w_{n}\in L({\cal A})$ \end_inset , existen \begin_inset Formula $y_{1},\dots,y_{m}\in\Sigma_{\epsilon}$ \end_inset y \begin_inset Formula $q_{0},\dots,q_{m}\in Q$ \end_inset con \begin_inset Formula $y_{1}\cdots y_{m}=w$ \end_inset , \begin_inset Formula $q_{m}\in F$ \end_inset y cada \begin_inset Formula $q_{j+1}=\delta(q_{j},y_{j+1})$ \end_inset . Tomamos la subsecuencia \begin_inset Formula $y_{p_{1}},\dots,y_{p_{n}}=w_{1},\dots,w_{n}$ \end_inset y queremos ver que, si \begin_inset Formula $p_{n+1}\coloneqq m+1$ \end_inset y \begin_inset Formula $(r_{0},\dots,r_{n})$ \end_inset es la secuencia de elementos de \begin_inset Formula $Q'$ \end_inset con \begin_inset Formula $r_{0}=q'_{0}$ \end_inset y cada \begin_inset Formula $r_{i+1}=\delta(r_{i},w_{i+1})$ \end_inset , entonces \begin_inset Formula $q_{p_{i+1}-1}\in r_{i}$ \end_inset y en particular \begin_inset Formula $q_{m}\in r_{n}$ \end_inset y \begin_inset Formula $r_{n}\in F$ \end_inset . Para \begin_inset Formula $i=0$ \end_inset , \begin_inset Formula $q_{0},\dots,q_{p_{1}-1}$ \end_inset cumple que cada \begin_inset Formula $q_{j+1}\in\delta(q_{j},\epsilon)$ \end_inset , luego \begin_inset Formula $q_{p_{1}-1}\in E(q_{0})=q'_{0}=r_{0}$ \end_inset . Para \begin_inset Formula $0 \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\Sigma$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\epsilon$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $q_{0}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\emptyset$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\{q_{1},q_{2}\}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $Q_{1}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta_{1}(q,a)$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $Q_{2}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta_{2}(q,a)$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \end_layout \end_inset \end_inset \end_layout \begin_layout Standard \begin_inset Formula $L_{1}L_{2}$ \end_inset es aceptado por \begin_inset Formula $(Q_{1}\sqcup Q_{2},\Sigma,\delta,q_{1},F_{2})$ \end_inset , con \begin_inset Formula $\delta$ \end_inset dada por \end_layout \begin_layout Standard \align center \begin_inset Tabular \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\Sigma$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\epsilon$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $Q_{1}\setminus F_{1}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta_{1}(q,a)$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $F_{1}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta_{1}(q,a)\cup\{q_{2}\}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $Q_{2}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta_{2}(q,a)$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \end_layout \end_inset \end_inset \end_layout \begin_layout Standard \begin_inset Formula $L_{1}^{*}$ \end_inset es aceptado por \begin_inset Formula $(Q_{1}\sqcup\{q_{0}\},\Sigma,\delta,q_{0},\{q_{0}\})$ \end_inset , con \begin_inset Formula $\delta$ \end_inset dada por \end_layout \begin_layout Standard \align center \begin_inset Tabular \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\Sigma$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\epsilon$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $q_{0}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\emptyset$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\{q_{1}\}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $Q_{1}\setminus F_{1}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta_{1}(q,a)$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $F_{1}$ \end_inset \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \end_layout \end_inset \begin_inset Text \begin_layout Plain Layout \begin_inset Formula $\delta_{1}(q,a)\cup\{q_{0}\}$ \end_inset \end_layout \end_inset \end_inset \begin_inset Note Comment status open \begin_layout Itemize \begin_inset Argument item:1 status open \begin_layout Plain Layout \begin_inset Formula $\supseteq]$ \end_inset \end_layout \end_inset Dado un NFA \begin_inset Formula ${\cal A}\coloneqq(Q\coloneqq\{q_{1},\dots,q_{n-1}\},\Sigma,\delta,q_{1},F)$ \end_inset , queremos construir una expresión regular que acepte el mismo lenguaje que \begin_inset Formula ${\cal A}$ \end_inset . Para ello consideramos tuplas de la forma \begin_inset Formula $(Q,\Sigma,\delta,q_{0},q_{\text{F}})$ \end_inset , donde \begin_inset Formula $Q$ \end_inset es un conjunto finito, \begin_inset Formula $\Sigma$ \end_inset es un alfabeto, \begin_inset Formula $q_{0},q_{\text{F}}\in Q$ \end_inset , \begin_inset Formula $q_{0}\neq q_{\text{F}}$ \end_inset y \begin_inset Formula $\delta:(Q\setminus\{q_{\text{F}}\})\times(Q\setminus\{q_{0}\})\to{\cal R}$ \end_inset , siendo \begin_inset Formula ${\cal R}$ \end_inset el conjunto de expresiones regulares sobre \begin_inset Formula $\Sigma$ \end_inset , y decimos que esta tupla acepta una cadena \begin_inset Formula $w\in\Sigma^{*}$ \end_inset si existe una secuencia de cadenas \begin_inset Formula $y_{1},\dots,y_{m}\in\Sigma^{*}$ \end_inset y una de estados \begin_inset Formula $r_{0},\dots,r_{m}\in Q$ \end_inset con \begin_inset Formula $w=y_{1}\cdots y_{m}$ \end_inset , \begin_inset Formula $r_{0}=q_{0}$ \end_inset , \begin_inset Formula $r_{m}=q_{\text{F}}$ \end_inset y, para cada \begin_inset Formula $i$ \end_inset , \begin_inset Formula $\delta(r_{i},r_{i+1})$ \end_inset acepta \begin_inset Formula $y_{i+1}$ \end_inset . \end_layout \begin_deeper \begin_layout Plain Layout Sean \begin_inset Formula $q_{0},q_{\text{F}}$ \end_inset distintos, empezamos con \begin_inset Formula $(Q\sqcup\{q_{0},q_{\text{F}}\},\Sigma,\delta',q_{0},q_{\text{F}})$ \end_inset , donde \begin_inset Formula \[ \delta'(q,r)\coloneqq\begin{cases} \epsilon, & (q,r)=(q_{0},q_{1})\lor(q\in F\land r=q_{\text{F}});\\ a_{1}\mid\dots\mid a_{k}, & \{a\in\Sigma\mid r\in\delta(q,a)\}=\{a_{1},\dots,a_{k}\}\neq\emptyset;\\ \emptyset, & \text{en otro caso}. \end{cases} \] \end_inset Es fácil ver que esta tupla acepta las mismas cadenas que \begin_inset Formula ${\cal A}$ \end_inset , y vamos a ir transformándola, llegando en cada paso a una tupla que acepta el mismo lenguaje pero con un estado menos, hasta llegar a una de 2 estados, que será de la forma \begin_inset Formula $(\{q_{0},q_{\text{F}}\},\Sigma,\delta_{\text{F}},q_{0},q_{\text{F}})$ \end_inset y aceptará las mismas cadenas que \begin_inset Formula $\delta_{\text{F}}(q_{0},q_{\text{F}})\in{\cal R}$ \end_inset . \end_layout \begin_layout Plain Layout Sea la tupla \begin_inset Formula ${\cal A}_{k}\coloneqq(Q_{k},\Sigma,\delta_{k},q_{0},q_{\text{F}})$ \end_inset con \begin_inset Formula $|Q_{k}|>2$ \end_inset y sea \begin_inset Formula $q_{\text{R}}\in Q_{k}\setminus\{q_{0},q_{\text{F}}\}$ \end_inset , \begin_inset Formula ${\cal A}_{k+1}\coloneqq(Q_{k+1},\Sigma,\delta_{k+1},q_{0},q_{\text{F}})$ \end_inset dada por \begin_inset Formula $Q_{k+1}\coloneqq Q_{k}$ \end_inset y \begin_inset Formula \[ \delta_{k+1}(q,r)\coloneqq(\delta_{k}(q,q_{\text{R}}))(\delta_{k}(q_{\text{R}},q_{\text{R}}))^{*}(\delta_{k}(q_{\text{R}},r))\mid\delta_{k}(q,r) \] \end_inset acepta el mismo lenguaje que \begin_inset Formula ${\cal A}_{k}$ \end_inset . \end_layout \begin_layout Plain Layout En efecto, si \begin_inset Formula ${\cal A}_{k}$ \end_inset acepta \begin_inset Formula $w$ \end_inset , existen \begin_inset Formula $y_{1},\dots,y_{m}\in\Sigma^{*}$ \end_inset y \begin_inset Formula $r_{0},\dots,r_{m}\in Q_{k}$ \end_inset tal que \begin_inset Formula $r_{0}=q_{0}$ \end_inset , \begin_inset Formula $r_{m}=q_{\text{F}}$ \end_inset , \begin_inset Formula $w=y_{1}\cdots y_{m}$ \end_inset y cada \begin_inset Formula $\delta_{k}(r_{i},r_{i+1})$ \end_inset acepta \begin_inset Formula $y_{i+1}$ \end_inset . Si \begin_inset Formula $r_{0},\dots,r_{m}\neq q_{\text{F}}$ \end_inset , esta secuencia sirve para \begin_inset Formula ${\cal A}_{k+1}$ \end_inset , pues cada \begin_inset Formula $\delta_{k+1}(r_{i},r_{i+1})=\cdots\mid\delta_{k}(r_{i},r_{i+1})$ \end_inset . En otro caso, sean \begin_inset Formula $00$ \end_inset ) con \begin_inset Formula $z_{0}\cdots z_{p}=y_{i+1}$ \end_inset , \begin_inset Formula $z_{0}$ \end_inset aceptada por \begin_inset Formula $\delta_{k}(r_{i},q_{\text{R}})$ \end_inset , \begin_inset Formula $z_{1},\dots,z_{p-1}$ \end_inset aceptadas por \begin_inset Formula $\delta_{k}(q_{\text{R}},q_{\text{R}})$ \end_inset y \begin_inset Formula $z_{p}$ \end_inset aceptada por \begin_inset Formula $\delta_{k}(q_{\text{R}},r_{i+1})$ \end_inset y basta cambiar \begin_inset Formula $y_{i+1}$ \end_inset por \begin_inset Formula $z_{0},\dots,z_{p}$ \end_inset en la secuencia e insertar \begin_inset Formula $q_{\text{R}}$ \end_inset \begin_inset Formula $p$ \end_inset veces entre \begin_inset Formula $r_{i}$ \end_inset y \begin_inset Formula $r_{i+1}$ \end_inset . \end_layout \end_deeper \end_inset \end_layout \end_deeper \begin_layout Section Propiedades de \begin_inset Formula ${\cal REG}$ \end_inset \end_layout \begin_layout Standard \begin_inset Formula ${\cal REG}$ \end_inset está cerrado bajo unión, concatenación, clausura, complemento, intersección y diferencia. \series bold Demostración: \series default Los 3 primeros son por definición. Si el DFA \begin_inset Formula $(Q,\Sigma,\delta,q_{0},F)$ \end_inset acepta el lenguaje \begin_inset Formula $L$ \end_inset , el DFA \begin_inset Formula $(Q,\Sigma,\delta,q_{0},Q\setminus F)$ \end_inset acepta \begin_inset Formula $\overline{L}=\Sigma^{*}\setminus L$ \end_inset , pues para cada cadena \begin_inset Formula $w$ \end_inset solo hay una secuencia de estados \begin_inset Formula $\{r_{0},\dots,r_{m}\}\subseteq Q$ \end_inset con \begin_inset Formula $r_{0}=q_{0}$ \end_inset y cada \begin_inset Formula $r_{i+1}=\delta(r_{i},w_{i+1})$ \end_inset y \begin_inset Formula $w$ \end_inset se acepta si y sólo si \begin_inset Formula $r_{m}$ \end_inset es final. Finalmente, \begin_inset Formula $L\cap M=\overline{\overline{L}\cup\overline{M}}$ \end_inset y \begin_inset Formula $L\setminus M=L\cap\overline{M}$ \end_inset . \end_layout \begin_layout Standard \series bold Lema del bombeo \series default , \series bold LBLR \series default o \series bold \emph on \lang english pumping lemma \emph default \lang spanish : \series default para \begin_inset Formula $L\in{\cal REG}$ \end_inset , existe \begin_inset Formula $p\in\mathbb{N}$ \end_inset , la \series bold \emph on \lang english pumping length \series default \emph default \lang spanish , tal que toda \begin_inset Formula $w\in L$ \end_inset con \begin_inset Formula $|w|\geq p$ \end_inset puede ser dividida como \begin_inset Formula $w=xyz$ \end_inset con \begin_inset Formula $|y|>0$ \end_inset y \begin_inset Formula $|xy|\leq p$ \end_inset de modo que \begin_inset Formula $xy^{k}z\in L$ \end_inset para todo \begin_inset Formula $k\in\mathbb{N}$ \end_inset . \series bold Demostración: \series default Sean \begin_inset Formula $(Q,\Sigma,\delta,q_{0},F)$ \end_inset un DFA que acepta \begin_inset Formula $L$ \end_inset , \begin_inset Formula $p\coloneqq|Q|$ \end_inset , \begin_inset Formula $w\in L$ \end_inset con \begin_inset Formula $n\coloneqq|w|\geq p$ \end_inset y \begin_inset Formula $\{q_{0},\dots,q_{n}\}\subseteq Q$ \end_inset con cada \begin_inset Formula $q_{i+1}=\delta(q_{i},w_{i+1})$ \end_inset . Como \begin_inset Formula $\{q_{0},\dots,q_{p}\}\subseteq Q$ \end_inset , existen \begin_inset Formula $i,j\in\{0,\dots,p\}$ \end_inset con \begin_inset Formula $i0$ \end_inset , \begin_inset Formula $|xy|=j\leq p$ \end_inset y, para \begin_inset Formula $k\in\mathbb{N}$ \end_inset , el DFA acepta \begin_inset Formula $xy^{k}z$ \end_inset con la secuencia de estados \begin_inset Formula $q_{0}\cdots q_{i}(q_{i+1}\cdots q_{j})^{k}q_{i+1}\cdots q_{n}$ \end_inset . \end_layout \begin_layout Standard El lenguaje \begin_inset Formula $\{0^{n}1^{n}\}_{n\in\mathbb{N}}$ \end_inset no es regular. \series bold Demostración: \series default Supongamos que lo sea y sean \begin_inset Formula $L$ \end_inset el lenguaje, \begin_inset Formula $p\in\mathbb{N}$ \end_inset una \emph on \lang english pumping length \emph default \lang spanish de \begin_inset Formula $L$ \end_inset , \begin_inset Formula $w\coloneqq0^{p}1^{p}$ \end_inset y \begin_inset Formula $w\eqqcolon xyz$ \end_inset una división dada por el lema del bombeo. Si \begin_inset Formula $y=0^{k}$ \end_inset , \begin_inset Formula $xy^{2k}z\notin L$ \end_inset porque tiene más 0s que 1s; análogamente, si \begin_inset Formula $y=1^{k}$ \end_inset , \begin_inset Formula $xy^{2k}z\notin L$ \end_inset , y si \begin_inset Formula $y=0^{k}1^{l}$ \end_inset con \begin_inset Formula $k,l>0$ \end_inset , \begin_inset Formula $xyyz\notin L$ \end_inset porque tiene un 1 seguido de un \begin_inset Formula $0\#$ \end_inset . \end_layout \begin_layout Standard Los autómatas finitos son demasiado sencillos para teorizar sobre lo computable o no computable debido a su falta de memoria. \end_layout \end_body \end_document