Operations on languages ·Concatenation: L L2={SiS2I S1E L1 and S2E L2} ·Union -L1UL2={s|s∈L1ors∈L2} ·Exponentiation: -L0={ε}L1=L L2=LL ·Kleene Closure -L-UL i=0 ·Positive Closure -=U2 CS308 Compiler Theory 6Operations on Languages • Concatenation: – L L = { s s | s ∈ L and s ∈ L } 1L 2 { s1s2 | s1 ∈ L1 and s2 ∈ L2 } • Union – L L { | L L } 1 ∪ L 2 = { s| s ∈ L1 or s ∈ L2 } • Exponentiation: – L 0 = { ε} L1 = L L 2 = LL • Kleene Closure Kleene Closure – L* = U ∞ i = 0 i L • Positive Closure – L + = U ∞ i L 6 i =1 CS308 Compiler Theory