intro W M w
a : Program
X : Formula
⊢ ∀ (W : Type) (M : KripkeModel W) (w : W), evaluate M w (~(⌈∗a⌉X)⋀(~X⋀⌈a⌉⌈∗a⌉X)) ∧ evaluate M w (~(⌈∗a⌉X)⋀(~⌈∗a⌉X))
a : Program
X : Formula
W : Type
M : KripkeModel W
w : W
⊢ evaluate M w (~(⌈∗a⌉X)⋀(~X⋀⌈a⌉⌈∗a⌉X)) ∧ evaluate M w (~(⌈∗a⌉X)⋀(~⌈∗a⌉X))