 
 
 
 
7.6 Introductions
Introduction tactics address goals which are inductive constants.
They are used when one guesses that the goal can be obtained with one
of its constructors' type.
7.6.1 Constructor num
This tactic applies to a goal such
that the head of its conclusion is an inductive constant (say I). The argument num must be less or equal to the numbers of
constructor(s) of I. Let ci be the i-th constructor
of I, then Constructor i is equivalent to Intros;
 Apply ci.
Error messages: 
- 
 
Not an inductive product
- Not enough Constructors
Variants: 
- 
 
Constructor This tries Constructor 1 then
 Constructor 2, ... , then Constructor n
 where n if the number of constructors of the head of the
 goal.
- Constructor num with bindings_list
 
 Let ci be the i-th constructor of I, then Constructor i with bindings_list is equivalent to Intros; Apply ci
 with bindings_list.
 
 
 Warning: the terms in the bindings_list are checked
 in the context where Constructor is executed and not in the
 context where Apply is executed (the introductions are not
 taken into account).
- Split
 Applies if I has only one constructor, typically in the case
 of conjunction AÙ B. It is equivalent to Constructor 1.
- Exists bindings_list
 Applies if I has only one constructor, for instance in the
 case of existential quantification $ x· P(x). 
 It is equivalent to Intros; Constructor 1 with bindings_list.
- Left, Right
 Apply if I has two constructors, for instance in the case of
 disjunction AÚ B. They are respectively equivalent to Constructor 1 and Constructor 2.
- Left bindings_list, Right bindings_list, 
 Split bindings_list
 Are equivalent to the corresponding Constructor i with bindings_list.
 
 
 
