how can it be that the rule "Aa -> aA" is context-sensitive? According to the definition, context-sensitive rules have to be like this form:
αAβ → αγβ where
A ∈ N, α,β ∈ (N∪Σ)* and γ ∈ (N∪Σ)+ Thanks.
Add a comment |
1 Answer
It depends on what you mean. If you scroll down the Wikipedia entry, you can see that, formally,
cB → Bc
does not fit the scheme, but it can be simulated by 4 rules that do fit it:
- c B → W B
- W B → W X
- W X → B X
- B X → B c
So Aa → aA is not a CSG rule in itself, but the langue it generates is. Perhaps whoever told you it is, was using it as a shorthand (you could expand the definition of CSG rules to include these types of things as "macros").
