FractionBoxOptions{...}

FractionLine

FractionLine is an option for cells that determines the thickness of the line separating the numerator and denominator of a fraction.

With the default setting FractionLine Automatic, the fraction line has a thickness equal to the default thickness of a line in that font. This is the thickness, for example, of lines in the hyphen (-) and underscore (_) characters.

With the setting FractionLine None, the fraction line has zero thickness; i.e. it is invisible.

With the setting FractionLine k, the fraction line has a thickness k times the default value.

MultilineFunction

MultilineFunction is an option for cells that determines if the numerator or denominator of a fraction is split across multiple lines if it is too long to fit on a single line.

With the default setting MultilineFunction Automatic, the numerator or denominator may be reformatted to extend across multiple lines. This may involve converting the two-dimensional fraction into a fraction that uses a "/". The point at which the line break is applied is indicated by a symbol.

With the setting MultilineFunction LineWrapParts, the numerator or denominator is linewrapped to fit in the available space, while retaining the two-dimensional form of the fraction. The point at which the line break is applied is indicated by a symbol.

With the setting MultilineFunction None, the numerator or denominator is not split across multiple lines.