Chomsky Normal Form Conversion Example

[@EasyTheory]

Correction (from Natnael Taye): at 10:12, I incorrectly drew an arrow from B -> S0, whereas I meant B -> S (I even say it correctly...). If you see anything else wrong, reply to this and I'll credit you here.

[@bhavesh.adhikari]

@ 12:03 why A goes to S° ? or is it just the way we do it? since we have introduced the new start S° that goes to S, it's pretty much the same duplication for A (which you mentioned afterwards) for substitution of S° as S° goes where S goes. so if A goes to S°(say), shouldn't B does the same ? btw your videos are so helpful. thank you very much

[@AcidCH]

the bob ross of CFGs himself, what a great video As many have said, this is just 100x better than my lecture content which is someone reading off a script. Hearing your unfiltered thoughts as you move through is great, and your explanations are easy to follow.

[@domc97]

what an underrated channel. The way you explained really helped!

[@EasyTheory]

Thanks very much

[@yeonlee5]

watched this just now. thank you from the bottom of my heart because I was so confused with the way it was being taught in the course I'm taking, but the way you explained it sounded so clear and easy to understand

[@ТамирланБельгибаев]

You will save my money and time, sir! Thank You!

[@EasyTheory]

You're welcome!

[@t-en-t2542]

Thank you from Germany. I have my final exams next week. Your videos definitely helped me a lot! Keep up the great work!

[@muhammed2174]

Saved me on my midterm this example!!

[@qwqqq2416]

Thank you Professor, I wish I had you at my college to teach this.

[@EasyTheory]

You're welcome!

[@eleman971]

final is in 7 hours. you are a life saver

[@gabriellouns]

it was really helpful. i finally understand CNF... wish me luck i have an exam tomorrow. thank you so much, sir!

[@natnaeltaye2279]

Thank you for your video. Super helpful! Just one question: At 10:06, why do we have a directed edge from B to S0? Shouldn't it be from B to S instead? because that's what the rule implies. Thank you.

[@EasyTheory]

Wow I didn't even notice that. Thanks!

[@llimta]

That was perfect! Thank you for this lesson

[@randomguy18632]

Now I get it! 3 hr collage voom meeting did not help.

[@momusic1427]

Thanks a lot man ! You are making things so simple to understand

[@juliangershwin]

At 10:07 you draw a line from B --> S0, shouldn't that be a line from B --> S? Wouldn't that change the final form? EDIT: No it wouldn't.

[@mertellialti]

but it was a mistake I think, or we think wrong? I'm confused...

[@juliangershwin]

@@mertellialti it was a mistake. However, I am pretty sure that the answer is the same.

[@jussef2057]

Wanted to write the same

[@MrPhilbs]

Thank you for your help! Great video

[@EasyTheory]

You're welcome!

[@QasimKhan-nd8og]

excellent explanation

[@stijnjongbloed1]

Thanks for the video!

[@امینجمالی-خ9ص]

great explanation

[@aleksandrkanygin2672]

Thank you, that's a great explanation. Maybe you have an example with brackets, for example with rules something like S -> A, A -> (S)A etc. It's just a bit confusing for me how we should treat brackets as terminal symbols i guess? Thank you for your explanations sir.

[@swafly]

I started last video (explaining what CNF is) with 😴😪faces. I ended up this video with 😅😌☺faces. Thanks a lot!

[@constantmackin]

Hi, you said A can go to S0 at 12:06 but there is no edge in the graph, how can it A to S0 then please?

[@to0ony3]

he made mistake, there is no way A can reach S0... his graph has mistake.

[@YoungFootballer]

much love

[@vimalathithand917]

Thanks!

[@Mike-ej9dg]

Hello. At 13.32 why didnt you copy the whole expression of B?

[@Yenaled1]

would you break 4 nonterminals into two Y variables? ex: ABCD --> Y1Y2 where Y1 = AB and Y2 = CD

[@jackcalisthenics6579]

I know this is late, but for anyone reading this: that is incorrect. Here is an example: X->CDEF becomes X->CY, Y->DEF and then in the next iteration we have X->CY, Y->DZ, Z->EF

[@unamattina6023]

why S is deleted from B in 12.33?

[@vikhyatsharma8138]

Like from India

[@deepeshkumar6717]

At the end S0 and S both are same . So can we remove S0 and make S as the starting variable.

[@humiracousary1790]

thank you sir.....

[@EasyTheory]

You're welcome!

[@joshuadelorbe4444]

great video

[@EasyTheory]

Thanks!

[@shadowlite18]

hello sir, hopefully you see this before i start my quiz, im wondering if the order of mixed var needs to be changed too? i learned from the vid that we need to change forms of (aA) by replacing it with another var X or Y but if the form is (Aa), do we still change it? or leave it as is?

[@shadowlite18]

additional question, when do we simplify the CFG(removing useless symbols)? do we do it before or after converting to CNF?

[@arkprince9413]

u should be an actor

[@EasyTheory]

I kinda am when I'm teaching ;)

[@mertellialti]

no one tried to do it in a different order... let me try

[@EasyTheory]

Most orders don't work - I've done a video where (I think) around 20 out of the 120 possible orders work.