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.
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..
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 ".
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.
It should be recursively enumerable and not recursive union non recursively enumerable, which is just a mouthful for complement of recursive set I think
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
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.
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!
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?
If the string belongs to an recursive language, then the string will halt and accept. If don't belongs to an recursive language, the the string will halt and reject.
Derively what he meant when he said accepted in a recursive language is it means the programme does not go into a loop it always ends up halting and deciding wehter it accepts or rejects.
I watch it at 2x speed and it is still soooooo booooring and repetititititive ;o This entire video could be replaced with a single picture. I can read myself.
He said undecidable languages are those which are not decidable. They can be partially decidable. See the second point of undecidable language at 5:09. Not having TM means that there is no TM which can accept it. If we feed undecidable language to some TM it will just loop.
@@arpitshukla8970 also when the undecidable language happens to be partially decidable, then there is definately a Turing Machine for it, isn't it so?
I'm confused about how undecidable language may sometimes be partially decidable. If it's partially decidable, isn't it a partially decidable language?
David Kim , a partially decidable language is a language for which the Turing Machine will halt sometimes and may not halt some other times. If the language acts so that the TM to never halts, then the partially decidable language acts as an undecidable language. It could make the TM halt, but it never does. So it is by definition undecidable.
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.
Greater explanation right here
Thank u buddy
🙏 thanks
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..
Thara bhai jogindar ab pass hoga😂 let me try your tactics 😊❤
Go to 7:10 to understand the entire video quickly
lol thanks
Nice
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 ".
true
X2.0. for all TM topics.
As always - an excellent lecture.
you just saved this topic of mine !! i was about to leave this for my tomorrow's exam :)
You explain this better than my university's lectures thanks so much
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.
undecidable language also has the partially decidable language in it so for that part turing machine is available
It should be recursively enumerable and not recursive union non recursively enumerable, which is just a mouthful for complement of recursive set I think
thanks for helping me get this CS degree bro.
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
Dhanyawad sirji❤❤
Did you get pay raise? Microphone quality sounds much better now? How much was the raise BTW
Thanks Neso Academy
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.
Sir superb teaching ...sir I want to get ur all videos.
Bht bht shukriya aap ka 😀
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...
Thank u very much sir , excellent lecture..
Thank u sir this vedio helped me a lot ...
very good note thank you
Thank you for teaching...
Thanku for this wonderful video
why cant my uni lecture be as succinct and clear cut as this guy?
Thank you for this video
OH GOOOOD. THANK YOU!
Thankyou sir
Perfect thank you Sir
A language is undecidable if it is not decidable 😅😅
😂😂
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!
Yes it's just more of a mathematical way of saying it.
loved it sir
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 ???
Thankyou
You are repeating the same thing thrice 😊but i understood bcs you repeatedly said the same thing
Thank you so much.
The whole video in a nutshell:- "Every 60 seconds in Africa a minute passes"
This theory has recently been debunked and the scientists are now claiming that it's actually every alternate 30 second
@@nostalgean acutally, recently an Indian guy on Neso Academy revealed that its every 4th 15 seconds that makes up a minute. You should be proud.
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?
If the string belongs to an recursive language, then the string will halt and accept. If don't belongs to an recursive language, the the string will halt and reject.
Derively what he meant when he said accepted in a recursive language is it means the programme does not go into a loop it always ends up halting and deciding wehter it accepts or rejects.
also when the undecidable language happens to be partially decidable, then there is definately a Turing Machine for it, isn't it so?
Does the partially decidable is the same meaning of the semi-decidable?
where can i find the problems of the above topic?
thank you sir
Could this not be explained with like...several examples...strugling to find examples
yeah, he just read the theory!
Any vitians?
Sir I did find recognizable and unrecognizable languess in ur lectures?
the best ones but at X 1.50 speed ... below that its too hectic to handle
Rakshan Agarwal 3.5x
thank youuuu
sir raat ko kithe hrs sleep lete ho??
Adha thapar yaha milega😀
Watch at 1.25 speed. Thank me later.
I think 2x is far better.
Hashik Donthineni take my like.
click on the X button on your browser. Thank me later.
I watch it at 2x speed and it is still soooooo booooring and repetititititive ;o
This entire video could be replaced with a single picture. I can read myself.
5x😅
exellent
sir but for undecidable there may be turing machine ??TTM does not exist for undecidable
An undecidable language does not correspond to any TM. He says this in the video.
He said undecidable languages are those which are not decidable. They can be partially decidable. See the second point of undecidable language at 5:09. Not having TM means that there is no TM which can accept it. If we feed undecidable language to some TM it will just loop.
@@arpitshukla8970 also when the undecidable language happens to be partially decidable, then there is definately a Turing Machine for it, isn't it so?
Partially Decidable languages are also known as Semi-Decidable languages, right?
I'm confused about how undecidable language may sometimes be partially decidable. If it's partially decidable, isn't it a partially decidable language?
David Kim , a partially decidable language is a language for which the Turing Machine will halt sometimes and may not halt some other times. If the language acts so that the TM to never halts, then the partially decidable language acts as an undecidable language. It could make the TM halt, but it never does. So it is by definition undecidable.
saved my life:)
4:56😂
😂 😂 😂 😂
Every 60 seconds in Africa a minute passes.
Very important point dude👍
😂🙃
You get a cookie
needs a Venn diagram
Or ip waalo jinka kal paper hai thoko like.