Decidability and Undecidability 

I would add some nuances to the last line of the table that can be misleading. There can be a TM for an undecidable language since an undecidable language can be partially decidable (in other words, recognizable). An undecidable language can have a TM if then, there is no TM for the complement language. To sum up, I would replace the last line by "No TM for that language OR for its complement". In other words, if there is no TM, then it is always undecidable. But if there is a TM, it can still be undecidable. I think it is important to mention this difference if you really want to master the relationship between decidable, partially decidable and undecidable.

As always - an excellent lecture.

You explain this better than my university's lectures thanks so much

very very very thank you sir.. i am vry poor in this subject but after watching your videos i gain knowledge and i have attempt my exam completely. and 2 example in my exam are same as in your vdo. thank you again. all credit for getting good marks goes to only you..

X2.0. for all TM topics.

Go to 7:10 to understand the entire video quickly

you just saved this topic of mine !! i was about to leave this for my tomorrow's exam :)

Thanks Neso Academy

Thank u very much sir , excellent lecture..

Thank you for teaching...

At 05:03 "An Undecidable Language may sometimes be partially decidable". That means sometimes undecidable languages may also have a TM. (Because as mentioned there, partially decidable languages are Recursively Enumerable and there exist TM for RE languages) I think, it should be like "If a language is not even partially decidable only then it is undecidable ".

Thank you for this video

OH GOOOOD. THANK YOU!

thanks for helping me get this CS degree bro.

Thank you so much.

very good note thank you

undecidable language also has the partially decidable language in it so for that part turing machine is available

Thanku for this wonderful video

Can a r recursively enumarable language also accidentally accept a word that is not in the language?

can i say undecidable languages as non recursive language ???

Dhanyawad sirji❤❤

Perfect thank you Sir

loved it sir

Thank u sir this vedio helped me a lot ...

Bht bht shukriya aap ka 😀

thank youuuu

what is the relation between decidable/undecidable with recursive/(recursive enumerable) languages? are decidable language an alias of recursive language(aka conceptually equal to each other)? Maybe a Van diagram will make the whole picture more clear. Thanks for the great lectures

Sir superb teaching ...sir I want to get ur all videos.

thank you sir

The portion on undecibility is very unclear. I've showed it to some others and for beginners to Turing Machines, the part where he introduces the definitions imply that undecidable languages include recursively enumerable languages. But the chart at the end contradicts this.

Does the partially decidable is the same meaning of the semi-decidable?

Thankyou sir

A language is undecidable if it is not decidable 😅😅

A language is partially decidable if it is RE but not REC so partially decidable and recursively enumerable are not exactly same but it is a subset of RE.

why cant my uni lecture be as succinct and clear cut as this guy?

Thankyou

There is a small problem I think. First you say that ALL strings in a recursive language will be accepted in a TM. Then you only say that the recursive language strings will halt the TM (both accept and reject). Which is the correct?

pahle mai sochta tha ki bhagvaan hai ki nahi , jo mujhe automata mai just pass kara de.... aur agle din mujhe neso academy youtube channel mila...

where can i find the problems of the above topic?

what is the relation between decidable/undecidable with recursive/(recursive enumerable) languages? are decidable language an alias of recursive language(aka conceptually equal to each other)? Maybe a Van diagram will make the whole picture more clear. Thanks for the great lectures!

also when the undecidable language happens to be partially decidable, then there is definately a Turing Machine for it, isn't it so?

saved my life:)

exellent

Sir I did find recognizable and unrecognizable languess in ur lectures?

4:56😂

Could this not be explained with like...several examples...strugling to find examples

sir but for undecidable there may be turing machine ??TTM does not exist for undecidable

the best ones but at X 1.50 speed ... below that its too hectic to handle

Adha thapar yaha milega😀

You are repeating the same thing thrice 😊but i understood bcs you repeatedly said the same thing

I'm confused about how undecidable language may sometimes be partially decidable. If it's partially decidable, isn't it a partially decidable language?

Any vitians?

You get a cookie

sir raat ko kithe hrs sleep lete ho??

Partially Decidable languages are also known as Semi-Decidable languages, right?

The whole video in a nutshell:- "Every 60 seconds in Africa a minute passes"

needs a Venn diagram

Watch at 1.25 speed. Thank me later.

Or ip waalo jinka kal paper hai thoko like.