> <\body> The Greek characters are obtained in using the -key. For instance, yields> and yields >. Similarly, , , and can be used in order to type bold, calligraphic, fraktur and blackboard bold characters. For instance, > yields>, yields> and > yields >. Greek characters can also be obtained as \Pvariants\Q of Latin characters using the -key. For instance, yields >. The -key is also used for obtaining variants of the Greek letters themselves. For instance, both and yield >. An alternative way to enter blackboard bold characters is to type the same capital twice. For instance, yields>. Some symbols admit many variants. For instance, > yields >, var> yields >, var var> yields >, var var var> yields >, and so on. You may \Pcycle back\Q among the variants using. For instance, var var S-var> is equivalent to var>. Many other mathematical symbols are obtained by \Pnatural\Q key-combinations. For instance, > yields >>, > yields >> and => yields >>. Similarly, yields >>, > yields >> and \ -> yields >>. The following general rules hold in order to enter mathematical symbols: <\description> >is the main key for obtaining variants. For instance, => yields >>, but = var> yields>>. Similarly, var var> yields >>, var var => yields >> and var var = var> yields >>. Also, yields> and yields the constant =exp>. >is used for putting symbols into circles or boxes. For instance, yields >> and yields >>. Similarly, yields >>. >is used for negations. For instance, yields >> and = /> yields >>. Notice that = var var /> yields >>, while = var var / var> yields >>. >is used after arrows in order to force scripts to be placed above or below the arrow. For instance, ^ x> yields >>, but ! ^ x> yields >. The logical relations > and > are obtained using and . The operators > and > are natural variants and . Various miscellaneous symbols can be obtained using the prefix. Notice that certain symbols with a different mathematical meaning are sometimes denoted in asimilar way; such symbols are called . For instance, the vertical bar can be used as aseparator for defining sets >=R\|x\0|}>>, but also as the binary relation \Pdivides\Q1001>>. Often, but not always, homoglyphs admit a different spacing. The most annoying ambiguity is between invisible multiplication and function application , which are entered using the shortcuts . In order to facilitate certain automated treatments of your documents, such as mathematical syntax checking, we incite authors to pay attention to the homoglyph problem when entering formulas. For more information on this issue and how can assist you to use the appropriate notations, we refer to our section on the . >