Context-free grammars (CFG) form a more powerful class of formal grammars than regular grammars and are often used to define the syntax of programming languages. Formally, a CFG consists of a set of nonterminal symbols N , a terminal alphabet Σ , a set P of productions (rewriting rules),...
---上下文无关语法(Context-FreeGrammars) :一个上下文无关语法是一个四元组2: 其中N是一组非终结符(non-terminal symbols...最近一周有些拖沓,静下来把第3,4周的笔记写了 这两周的主题都是PCFGs,不过从浅到深,逐层深化罢了,所以题目就用ProbabilisticContext-FreeGrammars 智能推荐 上下文无关文法 本文的部分...
It is known that the language equivalence problem is interreducible with that of multiple ambiguity for context-free grammars, a long-standing open question. In this work, we prove that computing distances corresponds to solving undecidable questions: this is the case for the L1, L2 norm, the ...
Bayesian Finite Mixture ModelPhrase ParsingMCMCInstead of using a common PCFG to parse all texts, we present an efficient generative probabilistic model for the probabilistic context-free grammars(PCFGs) based on the Bayesian finite mixture model, where we assume that there are several PCFGs and ...
Parsing with Context-Free Grammars and Word Statistics We present a language model in which the probability of a sentence is the sum of the individual parse probabilities, and these are calculated using a probabilistic context-free grammar (PCFG) plus statistics on individual words and how t......
CFGLib can perform a number of basic operations on context free grammars. If there are some operations you need, feel free to suggest them on theIssuespage! Representation and Acceptance CFGLib can be used to represent grammars and then use those grammars to parse terms: ...
We present a probabilistic model for constraint-based grammars and a method for estimating the parameters of such models from incomplete, i.e., unparsed data. Whereas methods exist to estimate the parameters of probabilistic context-free grammars from incomplete data (Baum 1970), so far for ...
fuzzyPSM: A New Password Strength Meter Using Fuzzy Probabilistic Context-Free Grammars 来自 掌桥科研 喜欢 0 阅读量: 227 作者:W Ding,D He,H Cheng,W Ping 摘要: To provide timely feedbacks to users, nearly every respectable Internet service now imposes a password strength meter (PSM) upon ...
In this work, we presented an extension of ProGED, an equation discovery method based on probabilistic context-free grammars, in the direction of discovering ordinary differential equations (ODEs). This extension can additionally learn ODEs from partial observations, where only a subset of the state...
We show that the left-corner approach provides an advantage over simple top-down probabilistic context-free grammars in parsing the Wall Street Journal using a grammar induced from the Penn Treebank. We also conclude that the Penn Treebank provides a fairly weak testbed due to the flatness of ...