Theory Of Computation (2160704)

BE | Semester-7   Winter-2018 | 27/11/2018

Q2) (a)

What are the closure properties of regular languages?

  • Union, Intersection and Complement Are The Closure Properties Of Regular Expressions
  • Suppose M1=(Q1,Σ,q1,A11) and M2=(Q2,Σ,q2,A22) accepts languages L1 and L2, respectively.
  • Let M be an FA defined by M=(Q,Σ,q0,A,δ), where
  • Q=Q1×Q1
  • q0=(q1,q2)
  • and the transition function δ is defined by the formula
  • δ((p,q),a)=(δ1 (p,a),δ2 (q,a))
  • for any pΣ Q1 and qΣ Q2 and a Σ then
  • if A={(p,q) | p∈A1 or q ∈ A2}, M accepts the language L1∪L2;
  • if A={(p,q) | p∈A1 and q ∈ A2}, M accepts the language L1∩L2;
  • if A={(p,q) | p∈A1 and q ∉A2}, M accepts the language L1 - L2;