regex - Is this a regular language? If so, what is it's regular expression? -

regex - Is this a regular language? If so, what is it's regular expression? -

b = {1^k y | k >= 1, y in {0, 1}* , y contains @ to the lowest degree k 1's }

is language regular? if so, how prove it, , how represent regular look in python?

this class work, if explain reasons , processes behind answer, it'd much appreciated.

the language have equivalent language:

class="lang-none prettyprint-override">b' = {1 y | y in {0, 1}* , y contains @ to the lowest degree 1 1}

you can prove b' subset of b, since status in b' same b, k set 1.

proving b subset of b' involves proving words in b k >= 1 belongs b', easy, since can take away first 1 in words in b , set y rest of string, y contain @ to the lowest degree 1 1.

therefore, can conclude b = b'.

so our job simplified ensuring first character 1 , there @ to the lowest degree 1 1 in rest of string.

the regular look (the cs notation) be:

10*1(0 + 1)*

in notation used mutual regex engines:

10*1[01]*

the dfa:

here q2 final state.

"at least" key solving question. if word becomes "equal", story different.

regex computer-science regular-language