Regular expression for DFA

Question

Can someone tell me if the DFA is properly attached?

I suppose to give DFA for a language that has the alphabet Σ = {a, b}

I need DFA for this ----> A = {ε, b, ab}

Answer 1

No, for several reasons:

• Your machine bab
• Your machine does not accept ab
• Your machine is not a DFA, at least some strict definitions

Regarding the first point: starting with q1, we see b, go to q2, see a, go to q3, see band go to q4what is accepted. We saw baband accepted it.

: q1, a, . "" . , a , ab.

: DFA , , - . .

Myhill-Nerode, , DFA . , b ab, ; a b ; b . aa, bb ba, ( ); ab ( b).

DFA. :

• ,
• b
• a
• aa

, b , . , aa , , DFA. , , :

• a (3), a a, (3). b (2), b b, (2)

• a (4), a to to b ba, aa , , b, (4) .

• a, aa (4). b, ab, b, (2).

• ; a b (4).

- :

q1 --a--> q3
 |        /|
 b  --b--< a
 | /       |
 vv        v
q2 -a,b-> q4 \
           ^ a,b
           \_/

:

q    s    q'
==   =    ==
q1   a    q3
q1   b    q2
q2   a    q4
q2   b    q4
q3   a    q4
q3   b    q2
q4   a    q4
q4   b    q4

Answer 2

, DFA .