# TOC | Regular expression to ∈-NFA

Prerequisite – Finite Automata Introduction, Designing Finite Automata from Regular Expression (Set 1)

**∈-NFA** is similar to the NFA but have minor difference by epsilon move. This automaton replaces the transition function with the one that allows the empty string ∈ as a possible input. The transitions without consuming an input symbol are called ∈-transitions.

In the state diagrams, they are usually labeled with the Greek letter ∈. ∈-transitions provide a convenient way of modeling the systems whose current states are not precisely known: i.e., if we are modeling a system and it is not clear whether the current state (after processing some input string) should be q or q’, then we can add an ∈-transition between these two states, thus putting the automaton in both states simultaneously.

**Common regular expression used in make ∈-NFA:**

Example: Create a ∈-NFA for regular expression: (a/b)*a

Refer for – Conversion from NFA to DFA, Minimization of DFA

## Recommended Posts:

- Star Height of Regular Expression and Regular Language
- TOC | Designing Finite Automata from Regular Expression (Set 4)
- TOC | Designing Finite Automata from Regular Expression (Set 2)
- TOC | Designing Finite Automata from Regular Expression (Set 3)
- TOC | Designing Finite Automata from Regular Expression (Set 1)
- TOC | Designing Finite Automata from Regular Expression (Set 5)
- TOC | Designing Finite Automata from Regular Expression (Set 8)
- TOC | Designing Finite Automata from Regular Expression (Set 6)
- TOC | Designing Finite Automata from Regular Expression (Set 7)
- Theory of Computation | Generating regular expression from finite automata
- Regular Expressions, Regular Grammar and Regular Languages
- How to identify if a language is regular or not
- Theory of Computation | Union & Intersection of Regular languages with CFL
- Benefits of writing GATE exam

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.