|definition=
<tex>
\begin{array}{r c l}\langle Expression \rangle & ::= & [\langle to Application \rangle ]\ \lambda\ \langle Variable \rangle\ .\ \langle Expression \rangle |\\ & | & lambda\langle Application Variable\rangle.\ Expression\\Expression \langle to Application \rangle & ::= & \langle Application \rangle to Application\langle Unary \rangle\ |\ \langle Unary \rangle\\\langle Unary \rangle & ::= & to '('\langle Expression \rangle ')'\ |\ \langle Variable \rangle\\\langle Variable \rangle & ::= & \langle to Char \rangle +\\\end{array}
</tex>
}}
В первом случае функция является просто переменной.
