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

Question

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.

Answer 1

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
...