13 lines
240 B
Text
13 lines
240 B
Text
Import tactic.
|
|
|
|
Variables a b c d e : Bool.
|
|
Axiom H1 : a => b.
|
|
Axiom H2 : b = c.
|
|
Axiom H3 : c => d.
|
|
Axiom H4 : d <=> e.
|
|
|
|
Theorem T : a => e
|
|
:= calc a => b : H1
|
|
... = c : H2
|
|
... => d : (by apply H3)
|
|
... <=> e : H4.
|