Theory: Difference between revisions
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* Type 0 of the [[Chomsky Hierarchy]], and a proper superset of CSLs | * Type 0 of the [[Chomsky Hierarchy]], and a proper superset of CSLs | ||
* Rewrite rule: α→β, where {α, β} are strings of terminals and non-terminals | * Rewrite rule: α→β, where {α, β} are strings of terminals and non-terminals | ||
* Recognized | * Recognized <i>but not decided</i> by [[Turing Machines]] (ie, any 'yes' answer can be verified, but 'no' cases might not halt) | ||
==Closures== | |||
{|class="wikitable borders" | |||
! class !! concat !! union !! intersection !! kleene !! setdiff !! complement | |||
|- | |||
| REG || Y || Y || Y || Y || Y || Y | |||
|- | |||
| CFL || Y || Y || n || Y || n || n | |||
|- | |||
| R || Y || Y || Y || Y || Y || Y | |||
|- | |||
| RE || Y || Y || Y || Y || n || n | |||
|- | |||
|} | |||
[[Category: CS GRE Prep]] | [[Category: CS GRE Prep]] | ||