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MathML is an XML based system that uses tags to help a website correctly format complicated equations. This page is a guide to the basic elements of MathML for writing equations. Equations in PetroWiki can also be rendered as images (most currently are shown as images).
A tag is used to help the website correctly format an equation. Tags are surrounded by angle brackets <> to denote the fact that they will not appear in the website text. An example of a simple MathML tag is <mi>, which denotes that the next letter in the sequence will be an identifier, generally a variable like “x.” Tags almost always come in pairs and surround each element of the equation. For example, a simple variable, x, would be written as <mi>x</mi>. The end tag has a forward slash to denote that it is the end of the expression.
Tags are often stacked inside each other, for example <mrow><mi>x</mi></mrow> . This is known as nesting. Nesting is used when multiple tags apply to a single number or variable, or if a tag applies to a large number of numbers or variables. Every equation will have some elements of nesting in it.
Commonly Used Tags
|<code>||</code>||This tag begins and ends every equation.|
|<math>||</math>||This tag is nested inside the <code> tag. It is required in every equation.|
|<mrow>||</mrow>||This tag groups elements in a horizontal row.|
|<mi>||</mi>||This tag denotes an indicator, such as a variable.|
|<mn>||</mn>||This tag denotes a number.|
|<mo>||</mo>||This tag denotes an operator, such as a +, -, =, etc.|
|<mtext>||</mtext>||This tag denotes text within an equation.|
|<msub>||</msub>||This tag attaches a subscript to a base.|
|<msup>||</msup>||This tag attaches a superscript to a base.|
|<msubsup>||</msubsup>||This tag attaches a subscript and superscript to a base.|
|<msqrt>||</msqrt>||This tag forms a square root around an element or elements.|
|<mspace/>||This tag is used as a spacer between elements|
Examples of MathML Code and Explanations
As with all equations, this one begins and ends with the <code> and <math> tags. Each element of the equation is correctly tagged as a number <mn>, indicator <mi>, or operator <mo>. A space tag <mspace/> has been included between each element and the operators to help spread out the equation a little, so it is easier to read.
Equations with Superscripts:
Superscripts use the <msup> tag to identify both a base and an exponent. The base is listed first, the exponent second, and both use the appropriate tags, nested inside the <msup> tag.
Equations with Square Roots:
The square root tag <msqrt> puts any element of an equation that is nested inside it under the square root symbol.
More Complicated Equations
This page gives a very basic overview of how to use MathML, but MathML is a powerful tool that can produce very complex equations. The internet is full of guides and tutorials to help produce more complicated equations using MathML.
The following links are a few tutorials and guides that might be helpful to you when working with MathML.