Lecture 32/65: Decidability and Decidable Problems 

Back to 360p! wooo moving up in the world after the slew of 240p videos. Thanks so much for making this playlist. It is an excellent resource.

For people who are wondering, a good argument for showing that a Turing Machine that simulates a DFA on a string ALWAYS halts would be: We know what the string is finite (so it doesn't go on forever). If the DFA given is a proper DFA, in other words, the machine won't brake with any string over the alphabet given, we know that at some point the TM simulating the DFA will stop at some state in the DFA (as string is finite). Hence the state may be an accept state or not => it always either accept or reject a string over the alphabet of the DFA.

I'm so mad I came up with your videos this late in the term. I appreciate the effort you put into this and I find it MOST USEFUL . Thanks

Perfect. Love your videos. So much clearer than my professor and his bullshit, complicated slides.

This is a great explanation of decidable languages and couldn't get my head around it until now. Thank you.

Best explanations ever! As always! Thank you!

Thanks for these amazing videos, learning too much while prepearing my automata final exam. Good job!

I like this course. Thank you.

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Really simplified the the concept...Thank you for your efforts.

Thank you for the detailed explanation, very helpful!

i appreciate ur work.

Thanks! Really helpful

Very useful video. Thanks a lot.

Lovely Awesome Explanation, Happy Teacher's Day from India (a bit belated)

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Thank you very much truly appreciated :)

very helpful videos, thank you!

I wish my lecturer can teach like you one day.

Thank You

where can i get your notes

Superb explanation.. thank very much...

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12:23 interesting, the turing machine that simulates regular language is not in type 3 but in type 1 and it is weaker than universal turing machine.

awesome Prof.

I thought Context Free Languages are decidable as are Context Sensitive?

Not sure how good this explanation is for the students that learning TM "decidability" for the first time but this is a VERY GOOD review before my Theory of Computation final. THANK YOU !

*Thank you sir*

where can i get your notes???

A bit confused... every context free language is decidable, but you say only some questions about context free languages are decidable but others are not?

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boring stuff...in a long video