APS House Style

No one expects you to be a mathematician or to know all the intricacies of statistics. However, having a basic command of the terminology and processes really helps when it comes to styling mathematical information. This section will give you some background on mathematical terms and some guidelines to help you style variables and equations.

The minus sign symbol is always indicated by the «minus» code (to avoid any confusion of the «minus» sign with a hyphen, en-dash, or em-dash).

The following table shows commonly encountered mathematical symbols, how they can be written out, and some information regarding the specific mathematical process. Words should not be changed to math signs if the meaning becomes less clear by doing so.

Symbol | Written Out Version | Notes |
---|---|---|

Symbols that can be changed to words in text |
||

+ | plus | Addition |

«minus» | minus | Subtraction |

× | times | Multiplication |

• | times | Multiplication |

* | times | Multiplication (change to × or •) |

÷ | divided by | Division |

/ | divided by | Division |

= | equals | |

~ | approximately, about | |

≈ | approximately equal to | |

< | less than | |

> | greater than | |

≤ | less than or equal to | |

≥ | greater than or equal to | |

Symbols that should not be written out |
||

≡ | is defined as | The exact mathematic definition |

≠ | does not equal | |

± | plus or minus | Statistical deviation |

√ | square root of | Square root function |

|…| | absolute value of | Absolute value |

∞ | infinity | |

∩ | intersection | |

Σ | sum of | Sum of the values of the following formula |

∫ | integral of | Integral of the following formula |

∆ | change in | Change in the following variable (over time) |

∂ | derivative | |

dt |
derivative | |

e |
exponent | |

exp | exponent | |

f |
function |

Insert spaces between numbers if the following mathematical symbols are used: ≈, ≡, <, >, =, +, «minus», ×, and ÷. Do not insert spaces between these symbols: /, |…|, ~, and %.

Do not use two math symbols before a number. Change the first symbol to its written out form and bump the second to the number. Two consecutive math signs are only acceptable if one of them is the equal sign (=).

Ranges and symbols used with negative numbers can be especially difficult to decipher. For example, does «minus»5-10 mean that the range was between «minus»5 to «minus»10 or from «minus»5 to (+)10? If this occurs, rephrase the range so that it goes "from" one value "to" the second, e.g., "The nerve was stimulated a voltage range from «minus»5 to «minus»10 mV." This does, of course, necessitate a query to the author to verify the values.