OT -- Re: random cover of a range

[Yigal Chripun]

Daniel de Kok wrote:
> On Tue, Feb 17, 2009 at 8:19 PM, Yigal Chripun<yigal100 at gmail.com>  wrote:
>> context-sensitive means that you need to have both the context and the
>> language phrase to derive "semantic" meaning.
>
> No, context-sensitive refers to the left-hand side of a grammar
> (rewrite) rule. A CFG is restricted in the sense that the left hand
> side of a grammar rule can only be one non-terminal. The right hand
> side can contain terminals, non-terminal, and epsilons. E.g.:
>
> NP -->  Det N
>
> is a valid CFG rule. An unrestricted grammar allows (one or more)
> terminals and non-terminals on the left hand side. A context-sensitive
> grammar is like an unrestricted grammar, but does not allow for
> epsilons on the left or right hand sides. Some surface strings can not
> be described by finite grammars that can be described by a
> context-free grammar, such as AnBn (n A's followed by n B's).
> Likewise, some surface strings can be described by an unrestricted
> grammar that can not be described by a context-free grammar (such as
> AnBnCn).
>
> We're not talking semantics here, just surface strings ;). Of course,
> extracting semantics can be a side-effect of parsing.
>
> Take care,
> Daniel

I was trying to be a bit more liberal than the strict mathematical 
definition since I was talking about human (natural) languages.
a context for natural languages contains more than what you described 
above. for instance, I can say the exact same sentence and reveres it's 
meaning by the intonation of my voice.