Editing Surreal number (section)

===Forms===
A ''form'' is a pair of sets of surreal numbers, called its ''left set'' and its ''right set''. A form with left set {{mvar|L}} and right set {{mvar|R}} is written {{math|{{mset| ''L'' {{!}} ''R'' }}}}.  When {{mvar|L}} and {{mvar|R}} are given as lists of elements, the braces around them are omitted.

Either or both of the left and right set of a form may be the empty set. The form {{math|{{mset| {{mset| }} {{!}} {{mset| }} }}}} with both left and right set empty is also written {{math|{{mset| {{!}} }}}}.