/sci/ - Science & Math

>>6325385
it's some CS magic.

maybe if you read what's before?

>>6325385
>CS education

>>6325385
author is an idiot. leading zeros have nothing to do with a numbers value and the 0011101 is a binary representation of the decimal number 29 which is prime isn't it?

>>6325419
OP here what to do now? I m stuck

>>6325385

The author's definition of "representation" is that the string coding a number (except 0) must start with a 1.

The string "0011101" doesn't qualify, so the decision that it is not a prime is easy, because it is not a number.

The string "11101" does represent a number, so further tests are required to determine if it is prime.

>>6325385
name of the book, page number. stat!

OP Here:
Book: Introduction to automata theory languages and computations by Ullman.
Pg 32

>>6325432
This. 0011101 is not a prime because it's not considered a valid number representation in the first place. The author probably uses a representation that allows a bijection between strings of the language and natural numbers.

>>6325432
This is wrong right "every integer excepts 0 has a binary representation that begins with 1"

>>6325432
this

>>6325445
>Ullman


Ullman's a fucking genius. Guy's scary smart.

Now, wtf didn't you read what's in the box right above the damn paragraph????

>>6325463
He might be genius but his English suck balls

>>6325432
He didn't define it. He used it in the sentence like it was a fact.

>>6325490
>another fool who can't read

see the whole page above.

WELL OP HERE:
I understood. From the point of view of validating a string of 0 and 1 as either prime or not, author meant that for instance a coder wrote 0011101 in his program then a "lexical analyzer" would discard it declaring it not to be prime for simple reason because of pattern mismatching(Here the pattern to follow is that every number must start with 1 expect 0,Why? because for obvious reason that adding zero before any integer or even binary of that integer is useless. Why would a lexical analyzer keep track of zeros rather it would make a rule that every integer except zero must start with 1). I am god.

>>6325490
>>6325482
These.

Ullman does have some problems with clarity sometimes. You have to think of what he is trying to say.

In this case, he says is wrong. He says, "every integer except 0 has a binary representation that begins with 1." This doesn't actually exclude other representations that begin with 0. But that is what he wanted to say. He often gets if-then propositions backwards.

If you go to the websites for his books, he will give credit to people who find mistakes in his books so he can correct them for future editions. I have about 10 corrections there myself. They are mostly about sloppy language like this--ideas that are true, but worded badly to make them false.

>>6325495
Thank you mate.
Did anyone notice captcha contains only {l,y,t,r,u,v,h,m,n,c}

>>6325508
This

>>6325385
>no representation for zero in binary


wtf am I reading

>>6325511
>2014
>still solves whole captcha
>still does free WORK for those evil Google billionaires

come on brah.

>>6325516
Clearly not the same thing we are reading.

>>6325517
Except most of that data is used for free services and it is in your own interest to help them.

>>6325517
Both words in 4chan captcha are in italics.
And also most of the words don't mean anything in English so there is a high probability that your statement is wrong.

>>6325546
Ok, seriously. How come nobody ever read the website of reCAPTCHA?
http://www.google.com/recaptcha/learnmore

>>6325533
>Except most of that data is used for free services and it is in your own interest to help them.

LOL no. They put adsense on those pages and charge advertisers. You just keep on working for free for billionaires!

>>6325517
> bothering with this shit

>>6325546
>Both words in 4chan captcha are in italics.
>And also most of the words don't mean anything in English so there is a high probability that your statement is wrong.

damn idiots.

>>6325559
Can u tell me what my captcha mean "hmfrultr thKlyt"
there is no fucking vowel in it.

>>6325385
Option 1: CS people being retarded as usual
Option 2: Little endian numbers and all primes but 2 are odd (start with 1)

Probably #1 as CS is the cesspool of academia

Also, >>>/g/ is that way.

>>6325577
>u
>no vowel
>u

>>6325565
Previously i had all italics captcha though

>>6325610
>Previously i had all italics captcha though

Probably because you were not logged into Google's Evil Server botnet.

Pic related.

PS: Don't do free work for billionaires.

>>6325559
>2014
>not using an ad filter
Why exactly should I care anyway? They can get as much money as they want from advertisers as long as they don't ask anything from me.

>>6325621
wow u made A quick gif for me!!

>>6325632
/facepalm

please tell me that was sarcasm. I refuse to believe people this dumb post on /sci/

>>6325629
well, then just keep on slaving for billionaires, pleb. it's your time they're stealing.

>>6325642
dumb detected

>>6325621
WHAT THE FUCK!?

>>6325691
>WHAT THE FUCK!?

google IS evil. news at 11.

http://cryptome.org/2013/08/assange-google-nsa.htm

>>6325621
Is the gif legit?

>>6327679
>Is the gif legit?

yes. try it yourself. log out of jewgle and see for yourself. it's not a secret:

http://googleonlinesecurity.blog
spot.com/2013/10/recaptcha-just-got-easier-but-only-if.html

this is not true

btw:
the captcha is not case sensitive
you do not need to type the scanned text AT ALL

>>6325621
someone explain this for me

>>6325621
> PS: Don't do free work for billionaires.
but I like having free books

>>6328109
Computer vision sucks so it's easier to have humans do things like digitizing books.
Google has had a goal for a while of digitizing EVERY book.
It then provides the books for free if they are in public domain

Google has been using captchas to do this goal while providing a turing test to sites like 4chan for authentication.

> Error: This CAPTCHA is no longer valid because it has expired. Please try again.
FUCK YOU GOOGLE

>>6328119
>but I like having free books

>implying they're free or that you can download them

Keep on slaving, beta. Do free work for billionaires… your time seems to be worthless to you.

>>6328133
>implying they're free or that you can download them
I've both downloaded and read them.

And CAPTCHA's are suppose to be turing tests anyway and computers suck at computer vision.