Context-Free Languages in 3.5 Hours (CFG, PDA, Conversions, Closure, Pumping Lemma)

Here we do a livestream covering everything to do with context-free languages. We cover context-free grammars (CFGs and two examples), pushdown automata (PDAs), the conversion from a CFG to a PDA, the conversion from a PDA to a CFG, the pumping lemma for context-free languages, and closure properties (as well as operations CFLs are not closed under). Timestamps: 0:00 - Start of livestream 21:19 - Start of topics 24:10 - Definition of CFG 31:20 - Example 1 of CFG (with definitions) 41:30 - Example 2 of CFG (balanced parentheses) 47:30 - CFLs closed under union, concat, star 59:40 - Chomsky Normal Form definition 1:09:11 - CFG to CNF start 1:13:38 - Step 1 of CNF conversion 1:15:22 - Step 2 of CNF conversion 1:20:05 - Step 3 of CNF conversion 1:23:53 - Step 4 of CNF conversion 1:28:12 - Step 5 of CNF conversion 1:39:50 - PDA definition 1:45:00 - PDA example 1:49:50 - CFG to PDA 2:01:10 - PDA to CFG 2:36:30 - Proof of Pumping Lemma for CFLs 2:55:40 - Pumping Lemma for CFLs statement 2:58:50 - Proving {0^n 1^n 2^n} is not a CFL 3:07:40 - CFLs not closed under complement or intersection 3:23:10 - Wrapup Donation (appears on streams): https://streamlabs.com/easytheory1/tip Paypal: https://paypal.me/easytheory Patreon: https://www.patreon.com/easytheory Discord: https://discord.gg/SD4U3hs #easytheory #gate #theory Youtube Live Streaming (Sundays) - subscribe for when these occur. Social Media: Facebook Page: https://www.facebook.com/easytheory/ Facebook group: https://www.facebook.com/groups/easytheory/ Twitter: https://twitter.com/EasyTheory Merch: Language Hierarchy Apparel: https://teespring.com/language-hierarchy?pid=2&cid=2122 Pumping Lemma Apparel: https://teespring.com/pumping-lemma-for-regular-lang If you like this content, please consider subscribing to my channel: https://www.youtube.com/channel/UC3VY6RTXegnoSD_q446oBdg?sub_confirmation=1 Gold Supporters: Micah Wood Silver Supporters: Timmy Gy ▶SEND ME THEORY QUESTIONS◀ [email protected] ▶ABOUT ME◀ I am a professor of Computer Science, and am passionate about CS theory. I have taught many courses at several different universities, including several sections of undergraduate and graduate theory-level classes.