# Default Document Math Properties

A number of math display properties have document defaults. These are the ones used if you don’t explicitly override them, which you can usually do by invoking a math context-menu option. The properties all pertain to “displayed” math zones, that is, math zones that begin either at the start of the document or at a hard/shift Enter (CR/VT) and end at the following hard/shift Enter. The options determine math indents and things such as whether integral limits are positioned below and above the integral or as subscript and superscript. In Russia, it’s common to see the integral limits below and above the integral, while in the United States the limits are displayed as subscript and superscript.

You can change the default settings to suit your tastes or a publisher’s conventions. In the math ribbon (type Alt+= to insert a math zone and then the math ribbon should appear), click on the Tools button over toward the left side of the ribbon. A dialog will be displayed that shows a variety of math display properties along with buttons to access the math autocorrect and recognized-function dialogs.

The document default math properties in this dialog are described in a somewhat technical way in the math section of the RTF specification. The properties belong to the RTF {\mmathPr…} group. They are also children of the <mathPr> OMML element. In this post, I describe the properties in a less technical way. For easy reference to the RTF specification, the relevant RTF control word is listed in parentheses. The dialog also has some options that are not document default math properties, such as “Copy MathML to the clipboard as plain text” instead of “Copy Linear Format to the clipboard as plain text.” Such options do not affect the layout of a document and hence are stored in the system registry rather than in the document.

**Default font for math zones (\mmathFont N)** Gives a drop-down list of math fonts that can be used as the default math font to be used in the document. Currently only Cambria Math has thorough math support, but others such as the STIX fonts are coming soon.

**Reduce size of nested fractions in display equations (\msmallFrac N)** Specifies that nested fractions should be displayed such that the numerator and denominator are written in a script or scriptscript size instead of regular-text size. Specifically characters in the outermost fraction’s numerator and denominator are displayed using the full text size, characters in a nested fraction are displayed in the script size (about 70% as large as the text size), and fractions nested inside a nested fraction are displayed in scriptscript size (about 60% as large as the text size). TeX uses this “small fraction” choice by default, but Word 2007 does not, basically because in all the physics books I’ve read I don’t remember seeing reduced sizes used in display math. But if you prefer them, you can change them.

**Break lines with binary and relational operators (\mbrkBin N)** Document property specifying how binary operators are treated when they coincide with a line break. By default, the line break occurs before the binary operator. That is, the binary operator is the first control word on the wrapped line. But you can change it so that a line break occurs after the operator, or so that the operator is duplicated, that is, it appears at the end of the first line and at the start of the second.

**Duplicate operators for subtraction as (\mbrkBinSub N)** Document property specifying how the minus operator is treated when it coincides with a line break when break operators are duplicated. By default, the minus appears before and after the break, but you can choose a plus before the break and a minus after the break or vice versa.

**Place integral limits to the side/centered above and below (\mintLim N)** Document setting for default placement of integral limits when converting from linear format to professional (built-up) format in display mode (not inline). Limits can be either centered above and below the integral, or positioned just to the right of the operator. The default setting is to position to the right of the operator (subscript/superscript).

**Place n-ary limits to the side/centered above and below (\mnaryLimN)** Document setting for default placement of

*n*-ary limits other than integrals when converted from linear format to Professional (built-up) format in display mode. Limits can be either centered above and below the

*n*-ary operator, or positioned just to the right of the operator. The default setting is above and below the operator.

**Use the following settings for math on its own line (\mdispDef N)** Document property to use the default math paragraph settings for equations, i.e., use values given by

**\mlMargin**,

*N***\mrMargin**,

*N***\mdefJc**,

*N***\mwrapIndent**,

*N***\mwrapRight**, etc. Default is to use the default math settings described below, but you can change it to use the text paragraph settings.

*N***Left margin (\mlMargin N)** Document property for the left margin for math. Math margins are added to the paragraph settings for margins.

**Right margin (\mrMargin N)** Right margin for math.

**Justification (\mdefJc N)** Document property for the default justification of displayed math zones. Individual equations can overrule the default setting. Displayed math zones can be left justified, right justified, centered, or centered as a group. When a displayed math zone is centered as a group, the equation(s) are ordinarily left aligned within a block, and the entire block is centered with respect to column margins. The user can use a context menu to align equations in more general ways, e.g., on the equal signs.

**Indent wrapped lines by (\mwrapIndent N)** Indent of wrapped line of an equation. The line or lines of a wrapped equation after the line break can either be indented by a specified amount from the left margin, or right-aligned. The default indent is 1”.

**Right align wrapped lines (\mwrapRightN)** If enabled, right justify wrapped lines of an equation. If disabled, the line or lines of a wrapped equation after the line break are indented by **\mwrapIndent N** from the left margin.

In addition to the properties above, the math RTF and OMML include four useful displacements for displayed math which unfortunately didn’t make it into Word 2007 (hopefully they will someday J). These properties are

**Spacing before math paragraph (\mpreSp N**).

**Intraequation spacing between lines in an equation (\mintraSp N)** .

**Spacing between equations within a display math paragraph (\minterSp N)** .

**Spacing after math paragraph (\mpostSp N)** .

In addition two useful, but not yet implemented, document default math properties are 1) math style for differential d and related characters (U+2145..U+2149), and 2) which character to use for invisible times (U+2063) if a line break occurs at the invisible times. Ordinarily one would use the \times (U+00D7) for a visible times character, but a raised dot is another possibility. In the United States, the differential d is almost always displayed as a math italic d, but in Europe, an upright d is fairly standard. The latter choice emphasizes that the differential d is different from regular mathematical variables. Similarly the Naperian logarithm base e (U+2147) and the imaginary unit i (square root of -1, U+2148) are displayed as math italic in the United States and upright in Europe.

The Equations Options dialog also includes buttons to examine math autocorrect entries and recognized functions such as trigonometric functions.

MathML doesn't formalize document defaults for math, but MathML math zones can inherit them depending on the implementation. So such defaults are compatible with MathML and need to be expressed in a way outside of MathML.