PUMPING LEMMA

a  theorem to check whether a language is regular/ non-regular
##   let L be a regular language then there exist a constant n (length of string) which depend on L . such that for every string w in L , and |W|>=n

• then we can break W into there substrings as W=XYZ such that

• Y>=1
• |XY|<=n
• for all i>=0, XYⁱZ is also in L

## we require a necessary condition for a string to follow to be the regular language . This result is pumping lemma.