Thank you so much for theses videos! I wish I could've found your video lectures at the beginning of this semester, they explain things way better in my opinion than my current professor at the college I attend. I will definitely be recommending them to anyone that asks in the future. Now let's just hope I can pass my final.
Thank you for the video ! I've finally understood the concept of pushdown automata and how it works ! By the way, first time when I saw you the description I thought your name was Harry Potter !!!
I think PDA at 16:30 is incorrect because all states states are connected with ε ? BEFORE first input symbol is read: trasition A->B pushes $ onto stack. Transition B->C does nothing but still happens because its conencted with ε. then transition C --> D happens because its connected with ε but this transition now pops the $ symbol that we pushed on the first strasition. Hence, before any symbol from the input is read the automaton pushes $ and then pops it leaving the machine broken ( C->D will never happen now because it won't encounter $ again). Am I wrong somewhere?
Ekrem Doğan You are correct. I should fix the example by adding the rules S-->0 and S-->1. But then I'd need to change the PDA to match. Since this is a somewhat minor flaw, I have decided not to re-do the video. But thanks for pointing it out! Next time...
Does the automaton compare the top of the stack with the input or not? What if in the last example there is 0 on input and 1 on top of the stack? 1 won't be popped?
Sorry, I can insert for example that my language accept double letters b than letters a for example abb, aabbbb, can I insert AA every time I read a letter a from the input string and when I read a letter b go unsaving a Letter A of the stacks, in summary I can insert in the stack two characters at a time regards
I wish the videos were in HD or at least 360p. They are very useful, but hard to read in some cases.
Thank you! Clear explanation. However, some texts were hard to read due to low resolution. I hope you can update them to HD versions in the future.
Thank you so much for theses videos! I wish I could've found your video lectures at the beginning of this semester, they explain things way better in my opinion than my current professor at the college I attend. I will definitely be recommending them to anyone that asks in the future. Now let's just hope I can pass my final.
Best video I have found on this topic. Thank you so much for the upload!
Hello, professor. Glad this video was up as I needed a refresher. I was in a computer ethics course with you a few years ago.
The content is very, very useful, and helped me a lot. Image quality is okay, readable. So thank you for uploading.
Brilliant explanation! Thank you for taking the time to make this.
Wow this was very helpful I'm studying for my exam and what my professor tried to explain in an hour I got from your video in just 20 mins, thank you!
Wish that more videos with examples from you.
Thank you for the video ! I've finally understood the concept of pushdown automata and how it works ! By the way, first time when I saw you the description I thought your name was Harry Potter !!!
You do an amazing job explaining this in such a simplistic manner! It would be great if you could post up problems and then solve them. Thanks again!
thank u sir, this lecture made me clear my backlog in this subject!!!!
I think PDA at 16:30 is incorrect because all states states are connected with ε ? BEFORE first input symbol is read: trasition A->B pushes $ onto stack. Transition B->C does nothing but still happens because its conencted with ε. then transition C --> D happens because its connected with ε but this transition now pops the $ symbol that we pushed on the first strasition. Hence, before any symbol from the input is read the automaton pushes $ and then pops it leaving the machine broken ( C->D will never happen now because it won't encounter $ again). Am I wrong somewhere?
I'm really sorry for all the Harry Potter comments you must get.
my jaw dropped
Doesn't help that when he says "pushdown automata", it sounds like he's casting a spell.
Great video. Simply shows what PDA is.
That language in 16:20 does not contain the word "111" eventhough it is a palindrome.
Ekrem Doğan You are correct. I should fix the example by adding the rules S-->0 and S-->1. But then I'd need to change the PDA to match. Since this is a somewhat minor flaw, I have decided not to re-do the video. But thanks for pointing it out! Next time...
If you want it to work with odd length words as well, add the rules "0, e -> e" and "1, e -> e" between B and C
8:54 What happens if there are more 1s than 0s?
Then the machine dies. Because when it can''t match any 1 on top of the stack with a zero, it has no transition to take and so the string is rejected.
Great Video! thanks professor!
Does the automaton compare the top of the stack with the input or not? What if in the last example there is 0 on input and 1 on top of the stack? 1 won't be popped?
Hello professor, thank you a lot, you helped me with my computational models subject a lot.
10 points to Griffindor!
Need better quality. Was this recorded with a potato?
You are helping me a lot with these videos, Thank you.
But.. it would be great if the videos are more clear, a bit hard to focus on reading.
so when you say 0,0->ε the automaton will (when ever read a 0 from the tape) and (when it sees a 0 on top of the stack it will pop it) and end?
Reads a 0 from the input string, pops a 0 from the stack, and pushed nothing back onto the stack.
Sorry, I can insert for example that my language accept double letters b than letters a for example abb, aabbbb, can I insert AA every time I read a letter a from the input string and when I read a letter b go unsaving a Letter A of the stacks, in summary I can insert in the stack two characters at a time
regards
Great video, thanks.
Example at 6:05
Great info !!!!
This guy's nam his so close to being so close.
Authomathaaah
thank you
much appreciated :)
The way he says automat-ah is so C3PO @ Jabba the Hut
thanks
$ rules, JFLAP drools!
jk rowling were your childhood friend?