Basic Elements

• The <math> element is the containing element for all MathML expressions.
• The <mn> element is used to designate literal numbers, such as $4$ or $2.75$, and typically rendered in a normal style with a special serif font.
• The <mi> element is used to designate an identifier, such as $\sin$ or $x$, and typically rendered in italics for single character variables.
• The <mo> element is used to designate an operator such as $+$ or $|$.
• The <mtext> element is used to designate short text inside an formula or statement, such as $\text{iff}$ or $\text{therefore}$.
• The <ms> element is used to represent a string literal, such as $''Hello\; World!''$, when the MathML is interpreted by programming languages and computer algebra systems.
• The <mspace> element adds space within an expression, using three parameters: depth, height, and width to specify the space below the baseline, the space above the baseline, and width of the space, respectively. For example, $xy$.
• The <merror> element is used to display content as an error messages. For example, $\text{An error}|\text{Not an error}$
• The <mrow> element is used to group together a set of elements so that they can be treated as one by the container.
• The <mfrac> element creates a fraction out of the two interior elements, while external operators are stretched vertically to match its height.
• The <msqrt> elementcreates a square root around the interior element.
• The <mroot> element creates a root around the first interior element with the second element designated as the fractional power.
• The <mover>, <munder>, and <munderover> elements are used to place symbols over, under, or both for special symbols like vectors, groupings, and summations.
• The <msub>, <msup>, and <msubsup> elements are used to place symbols as subscripts, superscripts, or both.
• The <mtable>, <mtr>, and <mtd> elements are used to create tables, row, and data elements for matrices or general layout control.
  • The columnspan and rowspan attributes can be used to size internal elements, much like standard tables.
• The <mmultiscripts> element allows for the place of subscripts and superscripts
  • The addition of a <mprescripts> element allows subscripts and superscripts to be placed before the main symbol: ${}_y{}^{z}C_w^x$
• The <mstyle> element is used to designate the style of the set of contained elements: $\sqrt{\frac{3}{2}}$.
  • Currently, all elements may be styled in this manner. So, this element functions much like the <mrow> element to group elements.
• The <annotation>, <annotation-xml>, and <semantics> elements are used to add presentation and content markup annotations and semantic meaning.

Stylistic Usage

• Using <mo> versus <mtext> versus nothing for parentheses: $f\left(x\right)$ versus $f\text{(}x\text{)}$ versus $f$($x$)
• $\frac{\text{Δ}x}{\text{Δ}y}$ versus $\frac{\Delta x}{\Delta y}$ versus $\frac{\mathrm{\Delta x}}{\mathrm{\Delta y}}$
• $\left|\frac{3}{4}\right|$ versus $\text{|}\frac{3}{4}\text{|}$
• $\left|x\right|$ versus $\text{|}x\text{|}$ versus |$x$|
• $\left(\genfrac{}{}{0ex}{}{n}{p}\right)$ versus $\left(\begin{array}{}np\end{array}\right)$
• $\sqrt{\frac{3}{x}}$ versus $\sqrt[5]{\frac{3}{x}}$
• The effect of display="block"
$$\sum _{i=1}^n$$
versus $\sum _{i=1}^n$
• Horizontal Stretching: $\overrightarrow{x+y_2}$

Applying Tables

• Function definitions:
$\mathrm{sgn}x:=\{\begin{array}{cc}-1& \text{if }x<0\\ 0& \text{if }x=0\\ 1& \text{if }x>0\end{array}$
• Equation Derivations:
$\begin{array}{ccc}1+2+3+\dots +n& =& \frac{n}{2}(n+1)\text{for }n\text{ even.}\\ & =& \frac{n-1}{2}(n+1)+\frac{n+1}{2}\text{ for }n\text{ odd.}\\ & =& \frac{n(n+1)}{2}\text{ for either case.}\end{array}$