Oui
Statement â
Let P and Q be two regular expressions.
If P does not contain null string, then R = Q + RP has a unique solution that is R = QP*
Proof â
R = Q + (Q + RP)PÂ [After putting the value R = Q + RP]
= Q + QP + RPP
When we put the value of R recursively again and again, we get the following equation â
R = Q + QP + QP2 + QP3âŚ..
R = Q (Îľ + P + P2 + P3 + âŚ. )
R = QP [As P represents (Îľ + P + P2 + P3 + âŚ.) ]
:D