Equations: Leave
a space after ln (natural log symbol).
Leave a space around operators in equations; do not leave a space after an operator used as a modifier (e.g., <50).
Do not punctuate equations.
Number all equations if any will be referred to. Enclose the number in brackets at the right margin of the center line of the equation. In text, refer to the equation as "Eq. [1]".
In the "where" list following an equation, define variables in the order of their appearance. Write the definitions as "=" the variable (e.g., x = the spot).
When an equation is complex, use parentheses to set parts off appropriately. Bracket parts of equations in the order {[()]}. If it is necessary to have a multiplication operator in addition to parentheses, use a vector dot.
All variables, whether in an equation or in running text, should be in italics. Numbers within equations should not be in italics.
Exponential or scientific notation: To clear repetition out of tables when possible, tie the notation to the unit in the heading rather than to the values, where it might be repeated hundreds of times. That will have the extra benefit of letting tables have larger fonts without taking up more space.
Non-range pairs: Treat non-range pairs of numbers as you would the range (e.g., "at 5 and 10 gpa").
Numbers in text: helvetica"> For a specific measured number that has an exact value, use the numeral. If two numbers occur in a row, for instance if you're talking about 6-m lines and there are two of them, spell out the one that's not attached to the unit (two 6-m lines).
For decimal numbers <1, use a lead zero to make sure the decimal point is visible. For integers without units, if the number is <10, spell it out. If the number is >9, use the numeral. Use greater than (>) and less than (<) symbols with numerals.
Ordinals: Spell out adjectival ordinals (e.g., first, second) in text and references; in tables and figures, abbreviation is acceptable.
Ranges: Use a dash in text as well as tables and figures (7–12). Units generally go at the end of the range or series (23–47 kV). The exception is units that are jammed against the numeral rather after a space; the jammed unit is repeated (10%–20%).
With ranges of complex numbers, show the
entire complex number at either end of the range (e.g., 2.6× 105–9.7× 105).
