• fdrake
    5.8k
    This forum has Mathjax support. Mathjax is a typesetting tool for mathematics.

    It turns

    (x)=(x/(n+1))*arctan(x*sqrt(sum_{i=1}^{\infty} \lambda_i)) into:



    through

    [math]\frac{x}{n+1}\text{arctan}(x*\sqrt(\sum_{i=1}^{\infty} \lambda_i)[/math]
    

    or

    Ex(~(x=y)&F(x))|-Ax(Px<=>Fx)

    into



    through

    [math]\begin{align}\exists x (\neg(x=y)\wedge F(x))\implies \forall x (Px \Leftrightarrow Fx)\end{align}[/math]
    

    To use Mathjax in a post, all you need to do is use to 'math' environment. This can be summoned by
    [math]...[/math]
    

    Useful logical symbols are:

    logical conjunction: is
    [math]\wedge[/math]
    
    logical disjunction: is
    [math]\vee[/math]
    
    negation: is
    [math]\neg[/math]
    
    existential quantifier: is
    [math]\exists[/math]
    
    universal quantifier: is
    [math]\forall[/math]
    
    forward implication: is
    [math]\Rightarrow[/math]
    
    backward implication: is
    [math]\Leftarrow[/math]
    
    biconditional is
    [math]\leftrightarrow[/math]
    

    see here for a long list, the far right column's 'Latex' symbols usually work

    Useful mathematical symbols are

    subset: is
    [math]\subset[/math]
    
    superset
    [math]\\supset[/math]
    
    belongs to
    [math]\in[/math]
    

    fractions: is
    [math]\frac{x}{y}[/math]
    
    subscripts and superscripts: is
    [math]x_1 ^2[/math]
    
    prime: is
    [math]\prime[/math]
    
    sigma notation: is
    [math]\sum_{i=1}^{i=n}[/math]
    
    note that you can bracket an expression with {} and Mathjax will treat it as a single expression in the intended place, whereas without {} it will usually treat what you write as two expressions. EG, if you want to obtain , you write
    [math]x^{21}[/math]
    
    rather than
    [math]x^21[/math]
    
    which gives the wrong thing )

    limits: is
    [math]\lim_{n\rightarrow\infty}[/math]
    

    you can write matrices or vectors using the \bmatrix environment

    1 0
    0 1

    can be represented as



    which is given by

    [math] \begin{bmatrix}1 & 0 \\ 0 & 1 \end{bmatrix} [/math]
    

    taking a new line is \\.

    If you are presenting a mathematical expression not inline consider wrapping what you write with:

    [math]\begin{align} ... \end{align}[/math]
    

    multi line derivations can be achieved by using \\ within the align environment.

    You can make things a lot prettier than I have here with more effort, but hopefully people take notice and logic posts become more readable.
  • fdrake
    5.8k


    Wasn't aware there's already a thread for it. I'll pin this one, thanks for including the reference.
  • andrewk
    2.1k
    I usually use \to for rather than because it is quicker to write, and more commonly used in logic texts. It's worth noting that changing to lower case the first letter of the code for any of the arrows above changes the symbol from a double to a single arrow, eg
    \leftrightarrow for instead of \Leftrightarrow for

    Other signs I've found useful in logic are \vdash for
    \bigcup_{j=1}^n for
    \bigcap_{j=1}^n for

    \bigvee_{j=1}^n for

    \bigwedge_{j=1}^n for
  • SophistiCat
    2.2k
    Nice. I hardly know any latex, so thanks for the convenient tutorial.
  • TheMadFool
    13.8k

  • TheMadFool
    13.8k
  • schopenhauer1
    9.9k


    Cool
  • TheMadFool
    13.8k
  • TheMadFool
    13.8k
  • TheMadFool
    13.8k


  • Wittgenstein
    442
  • Wittgenstein
    442
  • Wittgenstein
    442
  • Mephist
    352


    It works!!! :starstruck: :starstruck: :starstruck:
  • TheMadFool
    13.8k


  • TheMadFool
    13.8k


    edit (fdrake): \sum, it's a command.
  • Andrew M
    1.6k
    A handy feature I just found if you want to see the source of an equation in another post.

    Right-click on the math and select "Math Settings | Math Renderer | Plain Source" from the context menu. You will then see the text that goes between the [ math]...[ /math] delimiters. The default renderer is HTML-CSS.
  • Tristan L
    187
    1.
    2.
  • EnPassant
    665
    x =
    such that x =









  • Banno
    23.1k
    An odd case:



    It shoudl be



    It's

    \exists (x)(Px ) \exists ( y)( Py)(x=y)

    except without the space in ( y).

    Removing that space gives (y).

    Any other work arounds?

    from https://thephilosophyforum.com/discussion/comment/766524

    And what does it have to do with onigiri?
  • jgill
    3.5k


    I use Mathtype and set cut/paste to accomodate Wikipedia, then replace "<m.th>" by "[m.th]".

    In this example two empty spaces appear, between exists (x) and the other, exists (.). By closing the gaps one gets the proper symbols. I.e., exists(x) and exists(y).

    Odd. Notice that ( ) with a y inside produces a thumbs up: (y)
  • fdrake
    5.8k


    [math]\exists (x)(Px ) \exists \left( y \right) ( Py)(x=y)[/math]
    
  • Banno
    23.1k
    , Thanks!

    Yeah, but why?

    I gather the (y) gets processed before the math? Seems odd. Isn't spacing supposed to be irrelevant in Mathjax?
  • fdrake
    5.8k
    I gather the (y) gets processed before the math? Seems odd. Isn't spacing supposed to be irrelevant in Mathjax?Banno

    I imagine it's part of how plushforums parses the math environment.

    test:
    (y)
    
    (y)

    Seems to be just the math environment which has the weird parsing issue. Odd.
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