logo
In [1]:
import proveit
from proveit import A, B
from proveit.logic.booleans.implication  import iff_def
from proveit.logic.booleans.conjunction import left_from_and
from proveit.logic.equality import rhs_via_equality
theory = proveit.Theory() # the theorem's theory
In [2]:
%proving iff_implies_right
With these allowed/disallowed theorem/theory presumptions (e.g., to avoid circular dependencies), we begin our proof of
iff_implies_right:
(see dependencies)
In [3]:
iff_def
In [4]:
iff_def_spec = iff_def.instantiate({A:A, B:B})
iff_def_spec:  ⊢  
In [5]:
iff_def_spec.derive_right_via_equality(
    assumptions=iff_implies_right.conditions).derive_left()
iff_implies_right may now be readily provable (assuming required theorems are usable).  Simply execute "%qed".
In [6]:
%qed
proveit.logic.booleans.implication.iff_implies_right has been proven.
Out[6]:
 step typerequirementsstatement
0generalization1  ⊢  
1instantiation2, 3  ⊢  
  : , :
2theorem  ⊢  
 proveit.logic.booleans.conjunction.left_from_and
3instantiation4, 5, 6  ⊢  
  : , :
4theorem  ⊢  
 proveit.logic.equality.rhs_via_equality
5assumption  ⊢  
6instantiation7  ⊢  
  : , :
7axiom  ⊢  
 proveit.logic.booleans.implication.iff_def