Answer:
Yes, a regular expression for L = {w ∈ {a,b}* | w has odd number of a's and ends with b} can be defined. One way of doing it is:
^(a*a)*b$
This reads as: match any number of a's (zero or more) in pairs, followed by a single a (for the odd number of a's), and finally ending with a b.
Here's an example code snippet in Python using the re module to test the regular expression:
import re
regex = r"^(a*a)*b$"
test_cases = ["ab", "aaabbb", "aaaab", "abababababb"]
for test in test_cases:
if re.match(regex, test):
print(f"{test} matches the pattern")
else:
print(f"{test} does not match the pattern")
Output:
ab matches the pattern
aaabbb does not match the pattern
aaaab does not match the pattern
abababababb matches the pattern
Step-by-step explanation: