#Regular Expression

Question

Let ‘r’ be a regular expression, then which of the following statements is/are TRUE for every 'r'?

S1: There exists 'x' which satisfies property r + x = x.
S2: There exists 'x' which satisfies property r.x = x

Answer 1

Conncatanation with Φ is Φ. (r.Φ=Φ)

Both option ate true

 

Comments

is S1 true for every r as asked in the question?

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We put any value of r it must satisfied.

r+(a+b)*= (a+b)*

It is true for every r