While examining the package Library ZFC.Sets, I found the following definition:
Definition Paire : forall E E' : Ens, Ens.
intros.
apply (sup bool).
simple induction 1.
exact E.
exact E'.
Defined.
I don’t care, for the moment what is actually defined. What I do care about is that I don’t understand this syntax for definitions. Up to now, I’ve seen definitions follow the syntax of Definition name : statement . This definition, however, is paired with a Defined. at the end, and includes various tactics. My question is: What kind of a definition is this, and where can I read about such definitions?
