Nrule-25in0in5in The optional length moves the strut down from the baseline by a quarter inch. In certain cases it may be desirable to include normal text within an equation. The font type LaTeX uses in math mode is somewhat special since it is optimized for writing mathematical formulas.
It uses spacefactor to do thatThe problem is discussed in detail in in macro.
Some environments in LaTeX such as the align and equation environments do not require the sign to use math characters as they are automatically in math mode to. - a medium space - a thin space. Additional packages are necessary to produce natural number symbol and text command. The font type LaTeX uses in math mode is somewhat special since it is optimized for writing mathematical formulas.