lect13-cfl4

lect13-cfl4 - ThePumpingLemmafor CFLs Statement...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
1 The Pumping Lemma for  CFL’s Statement Applications
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Intuition Recall the pumping lemma for regular  languages. It told us that if there was a string long  enough to cause a cycle in the DFA for  the language, then we could “pump” the  cycle and discover an infinite sequence  of strings that had to be in the language.
Background image of page 2
3 Intuition – (2) For CFL’s the situation is a little more  complicated. We can always find  two  pieces of any  sufficiently long string to “pump” in  tandem. That is : if we repeat each of the two pieces  the same number of times, we get another  string in the language.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Statement of the CFL Pumping  Lemma For every context-free language L    There is an integer n, such that       For every string z in L of length >  n          There exists z = uvwxy such that: 1. |vwx| <  n. 2.
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 15

lect13-cfl4 - ThePumpingLemmafor CFLs Statement...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online