Question

what does this sign means ?

Answer 1

reversed A

Answer 2

for all

Answer 3

\thread

Answer 4

like if you say \(\forall n\in {\bf R}\)

Answer 5

what is thread ?

Answer 6

that means for all real numbers n

Answer 7

for all, that is the meaning

Answer 8

questions?

Answer 9

Just my way to saying that @SolomonZelman had it all. No need to get replies from other users

Answer 10

ok tnx . it means (for all)

Answer 11

tnx:) I saw that sign once, never used it tho' because no one qould get it, although it is a good tool to save space.

Answer 12

would*

Answer 13

Is that from a tutorial of a person who is obsessed with notations?

Answer 14

I don't really se it used alot... in any case, you now know it:)

Answer 15

yep i m proud i know it

Answer 16

I clicked on spraguer that I saw just now, and glitched:D

Answer 17

\[\forall x\in\mathbb{R^+}~x\gt \sin x\]

Answer 18

is their any link that gives informtion on all mathmatical signs and its meaning

Answer 19

look up quantifiers

Answer 20

\(0>\sin 0\) ?

Answer 21

0 is not a positive real number

Answer 22

oh forget that \(\huge \mathbb{R^{\color{red}{+}}}\)

Answer 23

you may think of \(\forall \) as a for/foreach loop in a programming language

Answer 24

\[\forall x\in \color{red}{X} ~ ~ \color{blue}{\text{statement}}\]

the \(\color{blue}{\text{statement}}\) is applicable to "all" the elements of set \(\color{red}{X}\)

Answer 25

i have also just seen reversed E

Answer 26

ok i see that sign \(\forall\) is from set theory

Answer 27

i have seen as "there exist" written as it meaning

Answer 28

\(\exists\) refers to existence of at least one that satisfies the statement that follows

Answer 29

\[\exists x\in \mathbb{R}~:~x^2=2 \]

means there exists at least one real number \(x\) "such that" the square of it equals 2

Answer 30

yes, lol, √2

Answer 31

or -√2

Answer 32

... ±√2

Answer 33

(i am using alt shortcuts)

Answer 34

can you guess what below statement means
\[\large \not \exists x\in \mathbb{Q}~:~x^2=2 \]

Answer 35

what is \(\large \mathbb{Q}\) ?

Answer 36

"set" of rational numbers

Answer 37

there exists no rational numbers that satisfy \(x^2=2\)

Answer 38

Yes, thats same as saying \(\sqrt{2}\) is irrational

Answer 39

\(\not \exists \mathbb{GM}:\text{GM}:\text{stockfish6.0} ::1:0\)

guess the statement

Answer 40

there doesn't exist a grandmaster who beat the stockfish 1-0

Answer 41

good one!

Answer 42

yep correct

Answer 43

it is important to mention stockfish version 6.0