Symbols and conventions

We have used the following conventions within this guide:

• Mathematical objects are presented in italics.
• Examples of commands, models and their output are printed in a Courier font. Filenames are given in lower case Courier.
• Decision variables have lower case names; in most example problems these are verbs (such as use, take).
• Constraint names start with an upper case letter, followed by mostly lower case (e.g. Profit, TotalCost).
• Data (arrays, sets, lists) and constants are written entirely with upper case (e.g. DEMAND, COST, ITEMS).
• The vertical bar symbol | is found on many keyboards as a vertical line with a small gap in the middle, but often confusingly displays on-screen without the small gap. In the UNIX world it is referred to as the pipe symbol. (Note that this symbol is not the same as the character sometimes used to draw boxes on a PC screen.) In ASCII, the | symbol is 7C in hexadecimal, 124 in decimal.