Question

Give a regular expression for these languages

i) {w| w is a word of the alphabet = {0,1} that represents an integer in a binary form that is a multiple of 4}

ii) {w belongs to {0,1,2}* | w contains the string ab exactly 2 times but not at the end}

iii) { w belongs to {0,1,2}* | w=uxvx that x belongs to {0,1,2} u,v belongs to {0,1,2}* and there isn't any string y in the sequence v that x<y}

Answer 1

i)

It accepts all the binary multiples of 4

ii)

It accepts all strings with exactly two ab and not ending in ab

iii)

Here x will not be less than any string y in v