Context Free Grammar & Context Free Language
ฝัง
- เผยแพร่เมื่อ 24 มี.ค. 2017
- TOC: Context Free Language
Topics Discussed:
1. Context Free Language
2. Context Free Grammar
3. Example of CFL generated using Context Free Grammar
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I didn't go to class for 4 months and passed the final exam with these videos. May the math gods bless your soul forever.
You did in less than 8 minutes what my professor couldn't do in an hour. Thank you
😂
my professor had 3 hours. also added im stupid. lol
@@dannggg my teacher had 3 as well but confused me so bad, I had to read the book twice. I am stupider :(
That's what heroes do🙌🙌
My professor finished in 5 minute so I want to study this clearly 😀
sometimes i feel i should pay the college fees to channels like this
no use of our faculty
oo bhai ap bhi yahan :-D
Same
This is the problem. Universities don't exist to make you learn anything. They are here because they are giving the knowledge on what to learn and how to learn it, how to think about it.
I know there are lots of institutions that are not doing its job done or well but this is the deal.
They are also gates before the work life just like some kind of pipeline.
This is similar to the education of the future, streamlined for a streamlined work environment, perhaps using an AI to help with the processes guidance and testing on the side of the business.
Free education for everyone will be needed when AIs impact the workforce and the economy as a result.
I agree. I am trying to learn this from Introduction to the Theory of Computation, and I wonder if they actually have people who know this see if they can learn it. I watch this and immediate understand. I go back and read it and it seems like its missing key information!
Thank you man. Your videos on Automata and Grammars are the only things which helped me truly understand them. Saved me in my class!
Exam tomorrow, 1.75 speed...Let's roll
Exam in 15min 2x roll!!
I love how there is always a comment like this under videos like these. Makes me feel less ashamed of procrastinating.
damn ... mine is also next week and doing the same lmao
@@shameelfaraz good luck
@Yash Raj 😂😂
Thank you sir. These last minute tutorials are so comprehensive yet very summarized and give the gist of the entire topic. Very helpful
Your tutorials helped me a lot in my last time preparation for my Exams.... Big thank you to you..And appreciating your work
Just a note. The difference between RG and CFG is regular grammar production rules are either left linear or right linear. But the rule doesr apply to production rules in CFG
This is an important point to note . You made things clear. Thanks ma'am ;-)
best teacher ever thank you so much....pls upload 65 to next lecture to complete full course of automata,,,,,,
First time I got a teacher who able to understand this subject clear cut..like...Haluaa.....very easy way ....this is the hard subject of CSE
Thank you so much! It has been a good 20 years since I've done anything with CFGs. This was exactly what I needed to reacquaint myself.
What are you studying them for?
I have been watching videos about context free grammar and context free languages for 3 days now, I also watched the lecture my professor put up more than 5 times and I am not exaggerating when I say I had a lot of difficulty understanding it but you did a great job, honestly so much respect. I finally got it
I'm honestly convinced that many professors who teach this don't understand it--or more importantly why it is important.
From the first class of Automata I'd been totally lost, I couldn't think of a way to get a good marks in this paper...These videos, as one of my class-mates suggested, helped me soooo soooo much...Atleast I'm confident now in this papaer, which is alone a huge leap forward for me...Many many thanks
I had no idea what was going on when we were discussing this during our three hours long lecture... I watched this and it makes sense, thank you!!
It's same effect in India. You From?
Neso Academy is one of the best Channel in TH-cam for studying all the subjects manely Formal language and automata theory each and every topic explanation is clear overthere . sometimes i feel that whatever money i m paying in college that is simply waste i have to pay all money to this channel who explained each and every topic clearly really proud of you sir these all videos are helpful for us.
you guys are too much you really save me from the stress or this course once again thank you and thank you
great effort by neso academy by introducing a one more course to your playlist.
in my 3 semester i study digital logic by neso academy and now toc in this semester.
i have a request sir please upload rest of the videos as soon as you can so that i can prepare more better for my end term which is going to start in one month.
happy neso learning.
My lecturer taught me this 2 weeks ago but i couldn't understand, but now its clear
for the first example, you should have just done Production Rule = (S-> aSb | epsilon) since a^0b^0 is also in the input for the question
It's really great and simple explanation of CFG
this man is hella amazing, my professor sucks for real!
best channel for learning....thank you neso academy
Great explanation and help provided this world...
Thank you for the explanation!
YOU'RE A LIFE SAVER
Backlog saver
@@anishgupta2380 jesus christ it's been 6 years since i've commented... my life has become so different now lol
Very clear explanation, thank you very much
Thanks for your help! Will subscribe!
Thank you,more useful ...better than our faculty .............
I am ethiopian software engneering 3rd year student your tetoiral is helpfull around course tanks so much .
THANK YOU SO MUCH.
Sir explained this topic very simple way..thank u sir
Thank you man!!!!
I think it should be
S -> aSb|€
Now it will also consider string when n = 0
Very good.
it depends on the value of n... probably in this case (example in the video)
n>=1
thanks to your videos i've earned A+ in midterm
you give the best explanation for the student thank you very much
You are awesome sir
Thanx alot
Thanks For your awsome tutorial
Lovely video. Thank you very much.
Thank you..Well explained..
thank you so much
explained it 100x better than my professor haha.
Thanks for the video King
Your English was impressive. Very understandable. Thanks
I mean when it's your first language....
very helpful
In 8 minutes you explained something I couldn't learn for a whole semester
Your explanation is os good
thanks nice work
awesome lectures. +NesoAcademy
Informative lecture.
Thank you Sir..
I passed my exam only because of u..
sir plz cover all topics of toc like
push down automate turing machine
Superb explanation tq sir
In example given ,Your solution doesnot accept "epsilon"
Thanks sir
Thanks
For me:
Basic definition of CFG and example
Please correct me if I am mistaken, but it seems that a = {V U E}^* allows a to be epsilon. However, Context free grammars do not allow the result of a production rule to be epsilon. Context free languages are a subset of context sensitive (non-contracting) languages, and even those do not allow production rules which gives epsilon as the output.
eg.
A -> epsilon is okay for level 0 unrestricted languages, but not level 1 context sensitive (non-contracting) nor level 2 context free languages. especially not level 3 regular languages.
The example taken @13:13 may be wrong since every CFG should also satisfy the rules for a Context Sensitive Grammar (Chomsky Hierarchy). The example has A -> aAb | ϵ, which is wrong since ϵ can only be written if the RHS has no non-terminal value that is already present in the LHS. ('A' in this case is present in both RHS and LHS, so ϵ cannot be written with it, if it is written then it is not a Context Sensitive Language thereby also making it a non CFL)
what about when n = 0? you can't get that using those production rules.
thanks
No words for u 🙏
Can I cite you and use your example for a presentation I'm doing on Probabalistic Abstract Context Free Grammars as applied to parsing jazz harmony? Great video!
Thankyou sir
This works assuming that n>=1, correct?
Since otherwise the cfg would have to be:
S-> aSb | epsilon
sir, pls cover at least all topic of the GATE in your lecture. Here you leave some topic in Regular language.
Thank you..
YOU ARE A GOD
exellent keep it up
For the last example can the CFG be S->aSb/ab/E
Thank you!
Neso Academy
EXAM Tommorow..2X lets gooo...✌✌
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1 question sir
Why A had been expanding only for 2 times?
Can we expand it further?
How about
S-> aSb / Epsilon?
it is sort of the same i cant see the diffrent btween all of them we have three diffrent grammer and they are the same to me
الله يكرمك كنت هسقط
In the start, you say that Regular Grammar can not generate languages of the form a^n, b^n. But in video titled 'Derivations from Grammar" in the same playlist, you do derive a a^m, b^n where m and n are greater than zero.
I know they are both not the same, but the later one (a^m, b^n ) is also infinite, so how can it be generated from a regular language?
You misunderstand. It is not infiniteness that makes it not possible to express the language a^n.b^n but the fact that both a and b have to be in equal quantities. It's not possible to keep track of How Many a or b were read and then match them up. You can try to find a solution yourself and see if you can or not.
Hello,as i know grammar type 2 has no restriction but i have to find a grammar type 1 that can not be of type 2.Please help me and show me an exemple.I need it for an exam.
Isn't A redundant, why can't we just use S-->aSb/epsilon, start symbol can be on right sidfe, right?
write CFG for the language L = {a^ib^jc^j:i,j>0} over the alphabet {a,b,c}.use leftmost and rightmost derivation to generate "aabbbcc". plz help sir!!! ( i m having the problem with leftmost and righmost derivation)
sir why not we stop at line 2 aaAbb by replacing A -> ε
this is the same example as of previous videos regular grammer's first example ....but u said it cant be derived by regular grammer
Sir, can you please provide lectures on Computer Networks.
#Excelent!
Thank you so fucking much I fucking love you!!!!!
why use A=aAb only two times? we can use it as many times as we want.
1:58 "4 element-tuple" , 4 tuples sounds like you have four different tuples (V),(E),(S),(P).
How do we know when we have to end the expansion ?
And when it should be ended?
Same question here.
If any of you both guys got your ans then pls post it here. Cause my exams are near.
First, thanks My friend
I have heard about empty string but not empty symbol.
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What is the difference between RG and CFG
It's the production rules bro.
Good
Dude can u please make a tutorial lec regarding 8086 microprocessor and its peripherals.......or can u recommend me any channel regarding the same
hahhaha @dude! u r funny man!
MAHESH RAJA UDAYAR l
Watch Bharat Acharya's Video...you'll become his fan
well said
ya watch bhrat acharay's video
Can you please tell me you guys where are you from?
Thanks!
Hello Necsco Academy, around 5:10 in this lecture I notice that you use the same symbol € for "element of" but also for "empty symbol or no symbol" That's kind of ambiguous isn't it? Maybe not such a good idea?
4:49
which grammar will be used to represent Indian language? Why not context free grammar?
People here are disrespectful to their college or uni teachers just you should know why you get it so clear here because the teacher in the class already set up your mind to it and as you hear it again you got it very clearly then blaming your teachers well you should try reading tomorow's topic of college in here then as you go to college you will think that your teacher is the best the real thing here is that you here and get the lecture twice thats why you understand it so good, this guy is a good teacher infact great but you should not give the real teacher's credit to this try seeing the lecture you missed in the class then that will be hard for you to understand