regexkleene-star

Does the kleene-star's potence 0 fulfill a disjunction?

Does the regular expression X•(Y*+Z) accept the word X?

I would say it does, as Y=ε should fulfill the disjunction, but I'm not sure.

Solution

  • Yes, matching 0 times still counts as success.

    Or, looking at it from the other direction, your regex generates

    X
XY
XZ
XYY
XYYY
XYYYY
...