Example of Non-Linear, UnAmbiguous and Non-Deterministic CFL?

可紊 提交于 2019-12-17 06:51:42

问题


In the Chomsky classification of formal languages, I need some examples of Non-Linear, Unambiguous and also Non-Deterministic Context-Free-Language(N-CFL)?

  1. Linear Language: For which Linear grammar is possible( ⊆ CFG) e.g.
    L1 = {anbn | n ≥ 0 }

  2. Deterministic Context Free Language(D-CFG): For which Deterministic Push-Down-Automata(D-PDA) is possible e.g.
    L2 = {anbncm | n ≥ 0, m ≥ 0 }
    L2 is unambiguous.

A CF grammar that is not linear is nonlinear.
Lnl = {w: na(w) = nb(w)} is also a Non-Linear CFG.

-- 3. Non-Deterministic Context Free Language(N-CFG): For which only Non-Deterministic Push-Down-Automata(N-PDA) is possible e.g.
L3 = {wwR | w ∈ {a, b}* }
L3 is also Linear CFG.

--4. Ambiguous CFL: CFL for which only ambiguous CFG is possible
L4 = {anbncm | n ≥ 0, m ≥ 0 } U {anbmcm | n ≥ 0, m ≥ 0 }
L4 is both non-linear and Ambiguous CFG And Every Ambigous CFL \subseteq N-CFL.

My Question is:
Whether all non-linear, Non-Deterministic CFL are Ambiguous? If not then I need a example that is non-linear, non-deterministic CFL and also unambiguous?

Given Venn-diagram below:

Also asked here


回答1:


"IN CONTEXT OF CHOMSHY CLASSIFICATION OF FORMAL LANGUAGE"

(1) L3 = {wwR | w ∈ {a, b}* }

  • Language L3 is a Non-Deterministic Context Free Language, its also Unambiguous and Liner language.

(2) Lp is language of parenthesis matching. There are two terminal symbols "(" and ")".
Grammar for Lp is:

S → SS
S → (S)
S → ()   
  • This language is nonlinear, deterministic and unambiguous too.

Language L that is union of Lp and L3 is unambiguous, nonlinear (due to Lp), and non-deterministic (due to L3) (Assuming language symbols for both languages are different).

This Language is an example of language in Venn-diagram for which I marked ??.

Also the correct diagram is below:

An ambiguous context free language also be a liner context free



来源:https://stackoverflow.com/questions/13143186/example-of-non-linear-unambiguous-and-non-deterministic-cfl

易学教程内所有资源均来自网络或用户发布的内容,如有违反法律规定的内容欢迎反馈
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!