What is Symbol: Definition and 377 Discussions

A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different concepts and experiences. All communication (and data processing) is achieved through the use of symbols. Symbols take the form of words, sounds, gestures, ideas, or visual images and are used to convey other ideas and beliefs. For example, a red octagon is a common symbol for "STOP"; on maps, blue lines often represent rivers; and a red rose often symbolizes love and compassion. Numerals are symbols for numbers; letters of an alphabet may be symbols for certain phonemes; and personal names are symbols representing individuals. The variable 'x', in a mathematical equation, may symbolize the position of a particle in space.
The academic study of symbols is semiotics. In cartography, an organized collection of symbols forms a legend for a map.

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  1. Ascendant78

    Resource for chemistry letter and symbol definitions/values in equations

    Homework Statement I have a chemistry teacher who discourages students from asking questions (long story, but he's just not a good teacher). We have an online textbook, which fails to explain a lot when it comes to formulas. One thing I want to understand is what the different letters and...
  2. M

    Understanding Set Theory and the + Symbol: Solving Equations with Sets

    Set Theory "+" symbol 1. X, Y and Z are sets. Does X × (Y + Z) = X × Y + X × Z? The solution starts like so: X × (Y + Z) = {(x,(y,0)) | x \in X, y \in Y}\cup{(x,(z,1)) | x \in X, z \in Z} I don't understand how the "+" symbol works. Why does it equate to this (x,(y,0)) (x,(z,1))...
  3. Barnak

    Interpretation of the integration domain symbol

    I'm having an interpretation problem with the notation used in physics, under the integration sign. What is the proper interpretation of the domain of integration symbol, on the integration sign ? To be more precise, consider a function F(x) of one or several variables. Its integral on a...
  4. C

    What does the word-final sigma symbol mean in maths?

    Hi all, I have spent a good half hour searching for the meaning of this, but have only found results for upper-case sigma Ʃ and lower-case sigma σ. Can anyone tell me the meaning of the "word-final" version of sigma, which looks like ζ ? I am trying to evaluate 3ζ(4) but I just need a...
  5. O

    Strange right-arrow symbol ([itex]\mapsto[/itex]) in stochastic calculus.

    What does the right arrow mean in this context: " ...Then the process t \mapsto \int_{0}^t \phi_s dM_s are well-defined continuous local martingales, whose quadratic variations are given by ... " Is this supposed to mean "the process X that is the mapping X: t \mapsto \int_{0}^t \phi_s dM_s"
  6. A

    Term Symbol of np3 & np2: What Are They?

    For np3, there is a term symbol: 4S I think it is because l are -1,0 and 1 So, L value=-1+0+1=0 However, for np2 , there is not a term symbol: 3S (I assume l are -1 and 1) I know I misunderstand something, but what are they?
  7. S

    Drafting question - weld symbol question

    Hey all, Not sure if things like this are dealt with here, but I'll give it a shot: I have a pipe with an outer "diameter A" (small) and a flange with an inner "diameter B" (large). Between them is a conical transition piece with the following characteristics: The OD of the cone at the small...
  8. R

    What math symbol would I use for never equal to

    What math symbol would I use for "never equal to" alright so I know that 1\neq 2 means that "1 is not equal to 2" right? so could I say that e^x\neq 0. Would this mean that e^x is never equal to 0? I know it seems small, but it confuses me a bit. also what would I say if I had a...
  9. B

    Levi Civita (Permutation) Symbol Proof

    Homework Statement Prove the following: \varepsilon_{ijk}= \left| \begin{array}{ccc} \delta_{1i} & \delta_{1j} & \delta_{1k} \\ \delta_{2i} & \delta_{2j} & \delta_{2k} \\ \delta_{3i} & \delta_{3j} & \delta_{3k} \end{array} \right| Homework Equations From my textbook: \hat{e}_3 = \hat{e}_1...
  10. P

    Is there a phonetic symbol that has the the three properties

    Is there a phonetic symbol that has the the three properties voiceless, glottal and fricative?
  11. S

    LaTeX Using the Symbol \Z for Integers in LaTex

    What's the best way to use Z as a symbol for the integers on the forum's LaTex? One source on the web (http://www.proofwiki.org/wiki/Symbols:Z) says the symbols for the integers can be written in LaTex as backslash Z. On the forum, that currently shows up as the two characters. \Z...
  12. X

    Evaluate expression with permutaion symbol and Kronecker delta

    Homework Statement Evaluate the following expression: \sum_{j}\sum_{k}\epsilon_{ijk}\delta_{jk} Homework Equations \delta_{ij} = [i = j]The Attempt at a Solution I don't have a solution attempt to this one yet, because somehow I completely missed out on what the permutation thing has to do...
  13. X

    Evaluating expression involving permutation symbol and Kronecker delta

    Homework Statement Evaluate the following expression: \sum_{j}\sum_{k}\epsilon_{ijk}\delta_{jk} Homework Equations \delta_{ij} = [i = j] The Attempt at a Solution I don't have a solution attempt to this one yet, because somehow I completely missed out on what the permutation thing...
  14. J

    Why use symbol & when using scanf in C?

    Why use symbol "&" when using scanf in C? When using scanf like in scanf("%d",&x); why do we use '&' before x? can't we write directly ,x as in printf command? Is it just a convention? I think it should have a reason.. they won't just put an "&" just like that
  15. A

    Subsets and sets symbol explenation (Very simple question please have a look)

    Homework Statement Hi I would like you please to look my attachement ,and explain to me the meaning of the line above M and N what's the meaning of this line?It seems to me that it acts as we should take the complementary collection of numbers . Homework Equations The Attempt at a...
  16. W

    What does the symbol Vdash mean?

    I would like to know what this symbol means:\nVdashSpecifically, in the main result of [link] (Theorem 1, at the top of p.4), it has:\nVdash(n=k=0)
  17. T

    Quick Question about the Christoffel Symbol of the Second Kind

    The Christoffel symbol is as followed: {\Gamma ^{m}}_{ab}=\frac{1}{2}g^{mk}(g_{ak,b}+g_{bk,a}-g_{ab,k}) where k is a dummy index. What values is it summed over? If I had to guess I'd say 0 to 3, but it seems somewhat counter intuitive. Does the Christoffel symbol become {\Gamma...
  18. M

    Positive/Negative Symbol Confusion

    So since we know that electrons are flowing in a relatively less negative (relative positive) direction why does + indicate source? Surely the electrons are flowing towards the + and not from it.
  19. S

    Java [Java] error:can not find symbol. I don't know what the hell is happening

    import java.util.Scanner; import static java.lang.System.out; import java.util.Random; public class wolf { public static void main (String[] args){ int hitpoints = 100; int damage = 40; //un numero cualquiera, solo para hacer una prueba Scanner keyboard = new Scanner(System.in)...
  20. C

    What is the symbol of an integral operator?

    Could someone please give a definition what the symbol of an integral operator is? Does it have asymptotic expansions as symbols of differential operators? I know about symbols of differential operators but, shame on me, heard nothing about the symbol of an integral operator. Any help in...
  21. H

    Expressions accompanying a Christoffel Symbol (a notation question)

    Just been reading on Christoffel Symbols and I am having a notational mind block. Say we have: \Gamma^{k}_{ij} v^{i} v^{j} The velocity depends on this expression, but I don't read this term v^{i} v^{j} as a velocity squared do I? It's just the one velocity, are the superscripts here...
  22. P

    Confused about +- symbol use in inverse function

    Hi, so this isn't a question, it's just an example that they've given, but I don't understand the explanation given. You have : y = x^2 - 4 x = y^2 - 4 y^2 = x + 4 y = ± sqrt(x+4) I don't get why there is a ± symbol there. My book says that it's necessary because there are two...
  23. H

    Christoffel Symbol dimension

    Homework Statement Homework Equations The Attempt at a Solution Does the Christoffel symbol \Gamma have a dimension in physics? And if it does, what is its dimension? Thank you!
  24. T

    Is there a math symbol that stands for becomes?

    Just curious because it would really work into a few problems I am doing
  25. D

    Circuit Symbol CR: Decoding the Mysterious Ref Designator in Diode Schematics

    Circuit symbol "CR" I have seen in some old schematics that diodes are labeled "CR" as a ref designator instead of D. I am just curious what the intention of this was since I have never seen a diode labeled with CR until now. CR = crystal rectifier or current rectifier?
  26. N

    [Number theory] Calculate the Hilbert symbol

    Homework Statement Determine the Hilbert symbol \left( \frac{2,0}{\mathbb F_{25}} \right) where the F denotes the field with 5² elements. Homework Equations \left( \frac{2,0}{\mathbb F_{5}} \right) = -1 The Attempt at a Solution Due to the formula that I put under "relevant equations"...
  27. S

    What symbol is used for linear operator actions?

    Given a vector v\in H: R2->R3 which is a function from R2 to R3, and an operator G: H->H on the space H in which v lives, what is the most commonly used symbol to refer to this mapping, i.e., G(v)=G\otimes v or something else?
  28. C

    Christoffel Symbol / Covariant derivative

    Homework Statement My teacher solved this in class but I'm not understanding some parts of tis solution. Show that \nabla_i V^i is scalar. Homework Equations \nabla_i V^i = \frac{\partial V^{i}}{\partial q^{i}} + \Gamma^{i}_{ik} V^{k} The Attempt at a Solution To start this...
  29. elfmotat

    Is the Sum of Christoffel Symbols Equal to Their Negative in Tensor Calculus?

    Is the following true? \Gamma_{\mu \nu \alpha}+\Gamma_{\nu \mu \alpha}=-2\Gamma_{\alpha \mu \nu} where: \Gamma_{\alpha \mu \nu}=g_{\alpha \sigma}\Gamma^{\sigma}_{~\mu \nu} I ask because, while bored in a philosophy lecture, I decided to try to derive the geodesic equation by extremizing...
  30. B

    Derivation of the value of christoffel symbol

    Hi, I am new to general relativity and as I would like to find out how we could derive the value of christoffel symbol in terms of the metric tensor. I have also heard that it was given as a definition for the christoffel symbol and would like a clarification on that. Regards Bltzmn2012
  31. J

    Writing a recursive function to compute the Jacobi symbol

    Write a recursive function to compute the Jacobi symbol J(a, n), is defined for relatively prime integers a and n, a> o, \mbox{ and } n > 0 by the formula J(a, n) = 1 \mbox{ if a = 1, } = J(a/2, n)*(-1)^\frac{n^2-1}{8} \mbox{ if a is even, } =J(n \% a, a)*(-1)^\frac{(a-1)*(n-1)}{4} \mbox{...
  32. M

    Need help figuring what this symbol means

    It's a line through two half circles. Specifically: Imagine about 40% of the bottom of a circle above about 40% of the top of a circle with a little space between them and then a vertical line starting above the circles and going through the middle of each circle and then finishing a...
  33. 3

    What is the meaning of the ∂ symbol in wave function equations?

    I have seen the ∂ symbol many times in wave function equations. What does it mean?
  34. Z

    How do you read this math symbol?

    Hi, I'm studying computation theory and this symbol that looks like a capital A without the middle bar is used to denote the empty string. What is it called? Thanks. EDIT: Looks like its a capital lambda?
  35. A

    When do you use ≡ and = in equations?

    How do you know when to use ≡ or =? I've seen the the formula for density written with that = and ≡. Also, whilst we're on the topic of symbols, what does an inequality sign with two lines beneath it mean? Is it the same as with one line (greater/less than or equal to) Thanks
  36. P

    Christoffel symbol from Variational Principle

    Homework Statement It's not exactly a homework question. I can find Christoffel Symbols using general definition of Christoffel symbol. But, when I try to find Christoffel Symbols using variational principle, I end up getting zero. I have started with the space-time metric in a weak...
  37. J

    Fewest number of segments to identify a know symbol

    This question started out as a thought experiment on a flight home from Japan a couple years ago. I've toyed with it since, but I don't know the best approach. I'm hoping someone can guide me in the right direction. I don't want the answer straight out, I'm mainly looking for a good way to...
  38. M

    LaTeX Troubleshooting Undefined Control Sequence for $\nexists$ in TeXShop

    Hello, everyone! First time poster. Quick question: I am working in TeXShop on a Macbook. When I type $\nexists$, I get an error message saying "Undefined control sequence" even though it is in the list of short course symbol tables available under the Help menu in TeXShop. $\not \exists$ works...
  39. J

    Tried finding out what this symbol means, but to no avail did not find it. Help

    Hi, Recently I've started an experiment called Quantum Wells, I was reading the lab script and came across a familiar looking symbol but could not put my finger on to what it means. The symbol in question is: Å (an upper-case "A" with a hollow dot [circle] just above of it) Here's the...
  40. Saladsamurai

    Write with at least one less abs value symbol

    Homework Statement Here we go. Write the following with at least one less absolute value symbol: (ii) |(|a+b| - |a| - |b|)| (iii) |(|a + b| + |c| - |a + b + c|)| (iv) |x2 - 2xy + y2| Homework Equations 12 Properties of Numbers. The Attempt at a Solution Let's just look...
  41. J

    Index notation - I never know when to introduce a new symbol?

    This isn't strictly a homework problem but anyway... I'm reading through a QFT textbook that is using index notation, and sometimes a new index symbol will be introduced during some mathematics and it always throws me off. I'll give a simple example, take the Minkowski metric: g^{\mu\nu} =...
  42. Q

    Levi-Civita Symbol: Understanding Rank 8 Tensor Properties

    I am reading Landau and Lifgarbagez's Classical Theory of Fields, 4th edition. In the beginning of page 18, the completely antisymmetric unit tensor is said to be a pseudotensor, because none of it components changes sign when we change the sign of one or three of the coordinates. Then, in...
  43. P

    Comp Sci Unresolved external symbol eror in fortran:solution?

    Mod note: Added code tags and formatted code. hello...i have been given an assignment which needs to be done on fortran90...i have come up with my code but it isn't working for me.. there are four parrts each specifying the values of M1 and angle for which M2 is to be calculated using...
  44. I

    What does a delta symbol mean in mathematics?

    In Spivak's calculus book he provides a proof for: Theorem: If f is continuous on [a, b] and f(a) < 0 < f(b), then there is some number x in [a, b] such that f(x) = 0. In the proof he explicitly says, "...A has a least upper bound \alpha and that a < \alpha < b. We now wish to show that...
  45. T

    What is the symbol for union and its significance in this context?

    This one in this context I never understood what it means and I can't find its meaning...
  46. B

    Does a symbol exist for this operation?

    (*)_pq = 1 if p> q else 0 This is kinda like kronecker delta in that its a relational operation. Any clue?
  47. G

    Where can I find a list of Christoffel symbols for calculation?

    Is there any book out there or website or something that has a list of christoffel symbols, something analogous to a table of integrals The amount of times I've had to calculate christoffel symbols by hand is unreal and let me tell you, chugging through tensors on a moving bus is hard enough...
  48. S

    What is the cause of these error- symbol 'x1' has no implicit type?

    Hi all, i am beginner in fortran and linux. I have wrote codes for 1d scalar wave as below: SUBROUTINE fd1d (x_num,x1,x2,t_num,t1,t2,c,u_x1,u_x2,u_t1,ut_t1,u) implicit none integer (kind=2) t_num,x_num,t,x real (kind=4)...
  49. P

    Do not understand symbol in homework

    My teacher, on the homework, posted what looked like a Reimman sum, except instead of a capital sigma, there was a Pi symbol instead. I never learned what that means or what its called. Can someone explain it to me?
  50. J

    What does this symbol mean (Countour integration over a boundary)?

    I keep seeing this symbol, something like \oint_{{\partial}\omega}\omega, I know it is a contour integral and read that {\partial}\omega is called a boundary, but I don't know what it means or why there isn't a differential at the end of it. Can someone please answer these questions and explain...
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