Introduction to Automata Theory Theory of Computation Lecture 5 Tasneem Ghnaimat

Non-deterministic FSA In DFSA, when machine is in given state, and reads the next symbol, we know that the next symbol is determined. In NFSA, there are many choices exist for the next state. NFSA may have the symbol (), Tasneem Ghnaimat

Example on NFSA (M1) 0,1 0,1 1 0, ε 1 Tasneem Ghnaimat q0 q1q2 q1 q3

Example on NFSA (M2) ε 0,1 1 0,1 q0q2 q1 Tasneem Ghnaimat

Example on NFSA State transition table for M2 Tasneem Ghnaimat 10 Φ q1 Φ q0 Φ q2 q1 q0q2

How to use NFSA After reading a symbol, if there are several paths, the machine splits itself into multiple copies, of itself and follows all possibilities in parallel. Each copy of the machine takes one of the possible ways and continues as usual. If any one of the copies is in accept state, the NFSA accepts the input string. Tasneem Ghnaimat