nLab
Sandbox

Click on the following links to jump to an anchor point. Of course, the same syntax works when linking to different pages, just replace “Sandbox” with the name of that page.

• jump to the first anchor point

• jump to the second anchor point

Linking to theorems and so forth is even easier. Make sure you use the numbered versions and give each one a label. For example:

+-- {: .num_defn #catdef}
###### Definition
A **category** has **objects** and **arrows** subject to some boring rules that I can never be bothered to remember.
=--

produces:

The key bit here is the #catdef. That produces the anchor just as in Urs’ examples. We can refer back to this definition using:

Definition \ref{catdef} is clearly missing something.

Definition 1 is clearly missing something.

One caveat: if you want to use references to numbered definitions and theorems and so forth then every numbered definition (etc) has to have a label, even if you don’t intend referring back to it. So if we have Definition 1 and Definition 2, and only intend referring back to Definition 2 then Definition 1 still has to have a label.

This only works with anchors produced in definitions and similar. So \ref{anotheranchor} doesn’t work. The converse, however, does work: we can use a link like this to point to the above definition. This also works from a different wiki page.

Now trying references to equations:

We should be able to refer to equation (1) explicitly, or to (1) if not.

But what if our equation is empty, like this?

Can we still refer to it via (2) or (2)?

Can we add anchors to pictures?

So we should now jump to that pic!

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Here’s a little experiment with the totally awesome all-new, all-singing, all-dancing WYSIWYG SVG editor from the totally awesome all-new, all-singing, all-dancing WYSIWIG Jacques Distler:

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XYPic diagrams using CodeCogs

This code here

  <img src="http://latex.codecogs.com/gif.latex?\xymatrix{(f/g)\ar[r]\ar[d]%26A\ar[d]^f\ar[dl]^\alpha\\B\ar[r]_g%26C}"/>

produces this xypic diagram picture:

Notice that all the ampersand symbols

  &

that you have in ordinary xypic code have to be replaced (unfortunately) by the symbols

  %26

otherwise the $n$Lab parser gets mixed up.

HTML parse error: 
<img src="http://latex.codecogs.com/gif.latex?\xymatrix{%26%26%26E\ar[dr]|{f_!}\ar@/^2.5pc/[ddrr]|=_{\%24}="s2"\\{*}\ar[dr]_A\ar@/^1pc/[urrr]^X_{\%24}="s1"%26%26 T\ar[ur]|{f^*}\ar[rr]|{=}^{\%24}="t1"%26%26T\ar[dr]|{f^*}^<{\ }="t4"\\%26E\ar[ur]|{f_*}^ />

”/>

Another diagram using \array:

$$\begin{array}{cccccccc}X& \cong & S_f^{{\Delta }^1}& \to & Y^{{\Delta }^1}& \to & S^{{\Delta }^1}& \\ & \searrow & \downarrow & \mathrm{Pb}& \downarrow & \mathrm{Pb}& \downarrow \\ L_f& \cong & S_{t\prime }& \to & L\prime & \to & L& \to & S^{\{1\}}& \\ & & \downarrow & \mathrm{Pb}& \downarrow & \mathrm{Pb}& \downarrow & \mathrm{Pb}& \downarrow p\\ & & {\Delta }^0& \to & ({\Delta }^1{)}^{{\Delta }^1}& \to & T^{{\Delta }^1}& \to & T^{\{1\}}\\ & & & \mathrm{id}& & (f{)}^{{\Delta }^1}& & d_1\end{array}$$\array{X&\cong&S^{\Delta^1}_f &\to &Y^{\Delta^1}&\to& S^{\Delta^1}& \\ &\searrow&\downarrow &Pb &\downarrow&Pb&\downarrow \\ L_f&\cong &S_{t'} & \to &L'&\to& L & \to & S^{\{1\}} & \\ &&\downarrow &Pb&\downarrow&Pb&\downarrow&Pb&\downarrow p \\ &&\Delta^{0} & \to &(\Delta^1)^{\Delta^1} &\to& T^{\Delta^1} & \to & T^{\{1\}} \\ &&&id&&(f)^{\Delta^1}&&d_1}

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Fonts.

• $𝒜$

Here is anchor point number 1!

$𝒪={\bigcup }_j{𝒪}_j$

$({\bigcup }_jℳ({𝒪}_j))″$

$ℳ(𝒪)$

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Here is the second anchor point.

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Some text $$x^2$$ some more text.

$$x^2$$x^2

some more text.

$${\int }_{j=1}^n\frac{1}{j}$$\int_{j=1}^n \frac{1}{j}

$$x^2+y^2$$x^2 + y^2

Axiom

(most important axiom)

Everything that I want to prove is true.

category: meta