Vim and summaries wood texture | Blog one Kibera
Today, the lectures on TA as always connects the projector, but the presentation was shown with laptop Struzha [1]. So my laptop was unoccupied, and included in rezetku. wood texture Accidentally wood texture opened workspace:
The process of note-taking and I got the idea to try to write a synopsis immediately wood texture electronically. And once the idea and started writing implement: r! Date. This ingeniously simple to just might Vim charms. wood texture
Text files have some limitations stovovno paper, but says the theory of text allows you to record any language. We only need to choose the correct grammar. Grammar I was very clear. The synopsis was written in strange pseudocode that is remotely reminiscent vikirozmitku, LaTeX, and C.
In principle why a lot to tell, the best show (just warning you, it's like a classic kospekt, there had to be clear. Besides the subject, though not belonging to the class of those that render wood texture the brain, wood texture but little zamudryy. People with unstable mentality wood texture better move down.): == ==== Lecture TA Lecture TA == Monday, October 26, 2009 8:41:14 +0200 === Properties of context-free languages === We study them because wood texture they are close to BNF. BNF is difficult to lay some claim. For example priorities of operations or condition that each variable must be described. Two components - theoretical multiple (functional), wood texture and (intentsionalna). What vlastyvoti can explore wood texture for grammar? Equivalence. wood texture Lemma (The renaming of nonterminals) wood texture If we Take another set of nonterminals having our biyektsiyu, the new grammar will be equal. In some cases, a context-free grammar can contain symbols and rules that are not used to output terminal chains. Example: We have a grammar G = ({S, A, B}, {a, b, c}, P, S), where P = {S-> a, S-> cS, A-> b}, nonterminal A and terminal B can not appear in any output chain. Takym way these characters are not involved in the generation of speech, and can be removed without changing the language that is displayed. To find unattainable grammar first define achievable grammar. This set is easily determined using inductive definitions: wood texture # R_0 = {S} # R_i = {B | is usually A-> \ alpha B \ b \ in P, that A \ in R_ {i-1}, B \ in N } \ cup R_ {i-1} i \ in N example: S-> a S-> A A-> AB B-> b C-> c Achievable: S, A, B. So just out of reach C, and it can be removed. # Define unproductive nonterminal wood texture (Tupikova) if it can not derive any terminal string. To find unproductive nonterminal must find all the productive terminals: Find grammar that immediately transformed into a set of terminal symbols. They definitely wood texture productive. Find the grammar that are converted into a set of terminal symbols and nonterminal symbols productive. C, B, S. A. Unproductive only removes all unproductive and inaccessible. And so a few times, because after we remove unproductive may be new unattainable. From the previous example will become the grammar S-> a, and it is equivalent wood texture to the example. # Define \ epsilon-rule - a rule type A-> \ epsilon Lemma: For each grammar we can construct an equivalent without epsilon rules. Example: S-> aSb S-> bSa S-> \ epsilon converted into S-> aSb S-> bSa S-> ab S-> ba Method: We each rule that contains the grammar involved in the epsilon rule do 2 ^ n new rules, where n - number of epsilon nonterminals, substituting instead nonterminals empty word in various combinations. Why do we build a grammar without epsilon rules? Because this grammar words only increase, because the exact finite wood texture output. And with epsilon wood texture rules hyz. # Define KV-grammar called the grammar in'' ''' Chomsky normal form' if its rules are of the form S-> \ epsilon, A-> a, A-> BC for some A, B, C \ in N, a \ in T. Lemma: For each grammar we can construct an equivalent grammar in Chomsky normal form. Break: Monday, October 26, 2009 9:32:26 +0200 conversion methods grammar in Chomsky normal form, do not understand S-> ASA S-> aSb S-> bSa A-> a transform: S-> ASA S-> DSB # define normal form Ghraib Its rules are of the form: A-> a \ alpha (ie, each rule starts with a terminal symbol). Sheila Ghraib - American researcher. This form is useful for every rule we receive at least one terminal, whereby the left. # Define recursive nonterminal wood texture (samovstavnyy, cyclic) if there is a withdrawal form A => * \ alpha A \ beta otherwise non-recursive nonterminal. If it is in an infinite recursive grammar is nonterminal. wood texture Conversely, if it is finite, it contains wood texture recursive grammar nonterminals. # Define regular word wtf? Lemma of the pump. View slides wood texture of ... Syntax === Operations on formal languages === Lemma language L3 = {a ^ nb ^ nc ^ n | n \ geq 0} is not context-free. # Proof by contradiction method. If we would L3 KV-language, then there would be a chain ut_1 ^ ixt_2 ^ iv \ in L3 \ forall i = 0,1, \ ldots. (And what was it?)
Today, the lectures on TA as always connects the projector, but the presentation was shown with laptop Struzha [1]. So my laptop was unoccupied, and included in rezetku. wood texture Accidentally wood texture opened workspace:
The process of note-taking and I got the idea to try to write a synopsis immediately wood texture electronically. And once the idea and started writing implement: r! Date. This ingeniously simple to just might Vim charms. wood texture
Text files have some limitations stovovno paper, but says the theory of text allows you to record any language. We only need to choose the correct grammar. Grammar I was very clear. The synopsis was written in strange pseudocode that is remotely reminiscent vikirozmitku, LaTeX, and C.
In principle why a lot to tell, the best show (just warning you, it's like a classic kospekt, there had to be clear. Besides the subject, though not belonging to the class of those that render wood texture the brain, wood texture but little zamudryy. People with unstable mentality wood texture better move down.): == ==== Lecture TA Lecture TA == Monday, October 26, 2009 8:41:14 +0200 === Properties of context-free languages === We study them because wood texture they are close to BNF. BNF is difficult to lay some claim. For example priorities of operations or condition that each variable must be described. Two components - theoretical multiple (functional), wood texture and (intentsionalna). What vlastyvoti can explore wood texture for grammar? Equivalence. wood texture Lemma (The renaming of nonterminals) wood texture If we Take another set of nonterminals having our biyektsiyu, the new grammar will be equal. In some cases, a context-free grammar can contain symbols and rules that are not used to output terminal chains. Example: We have a grammar G = ({S, A, B}, {a, b, c}, P, S), where P = {S-> a, S-> cS, A-> b}, nonterminal A and terminal B can not appear in any output chain. Takym way these characters are not involved in the generation of speech, and can be removed without changing the language that is displayed. To find unattainable grammar first define achievable grammar. This set is easily determined using inductive definitions: wood texture # R_0 = {S} # R_i = {B | is usually A-> \ alpha B \ b \ in P, that A \ in R_ {i-1}, B \ in N } \ cup R_ {i-1} i \ in N example: S-> a S-> A A-> AB B-> b C-> c Achievable: S, A, B. So just out of reach C, and it can be removed. # Define unproductive nonterminal wood texture (Tupikova) if it can not derive any terminal string. To find unproductive nonterminal must find all the productive terminals: Find grammar that immediately transformed into a set of terminal symbols. They definitely wood texture productive. Find the grammar that are converted into a set of terminal symbols and nonterminal symbols productive. C, B, S. A. Unproductive only removes all unproductive and inaccessible. And so a few times, because after we remove unproductive may be new unattainable. From the previous example will become the grammar S-> a, and it is equivalent wood texture to the example. # Define \ epsilon-rule - a rule type A-> \ epsilon Lemma: For each grammar we can construct an equivalent without epsilon rules. Example: S-> aSb S-> bSa S-> \ epsilon converted into S-> aSb S-> bSa S-> ab S-> ba Method: We each rule that contains the grammar involved in the epsilon rule do 2 ^ n new rules, where n - number of epsilon nonterminals, substituting instead nonterminals empty word in various combinations. Why do we build a grammar without epsilon rules? Because this grammar words only increase, because the exact finite wood texture output. And with epsilon wood texture rules hyz. # Define KV-grammar called the grammar in'' ''' Chomsky normal form' if its rules are of the form S-> \ epsilon, A-> a, A-> BC for some A, B, C \ in N, a \ in T. Lemma: For each grammar we can construct an equivalent grammar in Chomsky normal form. Break: Monday, October 26, 2009 9:32:26 +0200 conversion methods grammar in Chomsky normal form, do not understand S-> ASA S-> aSb S-> bSa A-> a transform: S-> ASA S-> DSB # define normal form Ghraib Its rules are of the form: A-> a \ alpha (ie, each rule starts with a terminal symbol). Sheila Ghraib - American researcher. This form is useful for every rule we receive at least one terminal, whereby the left. # Define recursive nonterminal wood texture (samovstavnyy, cyclic) if there is a withdrawal form A => * \ alpha A \ beta otherwise non-recursive nonterminal. If it is in an infinite recursive grammar is nonterminal. wood texture Conversely, if it is finite, it contains wood texture recursive grammar nonterminals. # Define regular word wtf? Lemma of the pump. View slides wood texture of ... Syntax === Operations on formal languages === Lemma language L3 = {a ^ nb ^ nc ^ n | n \ geq 0} is not context-free. # Proof by contradiction method. If we would L3 KV-language, then there would be a chain ut_1 ^ ixt_2 ^ iv \ in L3 \ forall i = 0,1, \ ldots. (And what was it?)
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