External

Syntax call
External[ , ... , ]
Input
a sequence , ... , of Mathematica expressions.
Output
the list { , ... , } where 1<= "ï<=<=n such that is not an already declared function symbol
Effect
declare , ... , as external function symbols by extending the default definition of IsExternal
and append to $FunctionSymbol the pairs {,} where is the arity of , 1 <= j <= m ;
assign to the type ∀.
Implementation