1.分别写出描述以下语言的正规文法和正规式:
L1={abna|n≥0}。
L2={ambn|n≥1,m ≥1}
L2={(ab)n|n≥1}
(1) 正规文法:S -> aAa
A -> bB | ε
B -> b | ε
正规式: ab*a
(2) 正规文法:S -> AB
A -> aA | a
B -> bB | b
正规式: aa*bb*
(3) 正规文法:S -> A
A -> (ab)B
B -> (ab) | ε
正规式: (ab)(ab)*
2.将以下正规文法转换到正规式
Z→0A
A→0A|0B
B→1A|ε
A = 0A+0(1A+ε)
= 0A+01A+0
= (0+01)A+0
= (0|01) | 0
Z = 0(0 | 01)*0
Z→U0|V1
U→Z1|1
V→Z0|0
Z = U0+V1
= (Z1+1)0+(Z0+0)1
= Z10+10+Z01+01
= Z(10+01)+(10+01)
= Z(10 | 01) | (10 | 01)
= (10 | 01)*(10 | 01)
S→aA
A→bA|aB|b
B→aA
A = bA+a(aA)+b
= bA+aaA+b
= (b+aa)A+b
= (b | aa)A | b
S = a(b | aa)*b
I→l|Il|Id
l = l+ll+ld
= l+(l+d)l
= l | (l | d) | l
= l(l | d)*