<\body> Since there are many keyboard shortcuts, it is important to have some ways of classifying them in several categories, in order to make it easier to memorize them. As a general rule, keyboard shortcuts which fall in the same category are identified by a common prefix. The active prefixes heavily depend on the selected ``look and feel'' in . In the current look and feel of your system,the main common prefixes are as follows: <\description> >Standard shortcuts, which are similar to shortcuts used by other applications (for the selected look and feel). For instance, can be used for pasting text on your system. > shortcuts, which often rely on the current editing mode. For instance, produces text in text mode and a square root > in math mode. >Compound shortcuts. Usually, these shortcuts first indicate the kind of markup to which the command will apply and then specify the specific command. For instance, the prefix is used for insering executable markup, which is useful for . One example is the shortcut for the insertion of an addition. >This prefix is used in combination with arrow keys and certain other special keys for >This prefix is used in combination with arrow keys and some other special keys for . >This prefix is occasionally used in combination with letters and ponctuation symbols for creating some additional easy to remind shortcuts. >This prefix can be used in combination with normal letters for the insertion of special symbols. For instance, yields ÿ and yields >>. The prefix is also used for the insertion of ``literal characters''. For instance, will always produce the \\ character, whereas the key is used for entering . Unfortunately, -based shortcuts are superseded by system shortcuts on several systems. For instance, accented characters and common special symbols are entered using this prefix under . In that case, you may use the key as an equivalent for . For more information, we refer to the section on . <\initial> <\collection>