finite-automataautomatacomputation-theoryformal-languageschomsky-hierarchy

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


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:

enter image description here

Also asked here


Solution

  • "IN CONTEXT OF CHOMSHY CLASSIFICATION OF FORMAL LANGUAGE"

    (1) L3 = {wwR | w ∈ {a, b}* }

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

    S → SS
    S → (S)
    S → ()   
    

    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

    dcf