cases em ¬(∃ Lcond Rcond C, Nonempty (LocalRule (Lcond, Rcond) C) ∧ Lcond ⊆ LR.1 ∧ Rcond ⊆ LR.2)
LR : TNode
⊢ Nonempty (LocalTableau LR)
case inl
LR : TNode
h✝ : ¬∃ Lcond Rcond C, Nonempty (LocalRule (Lcond, Rcond) C) ∧ Lcond ⊆ LR.1 ∧ Rcond ⊆ LR.2
⊢ Nonempty (LocalTableau LR)

case inr
LR : TNode
h✝ : ¬¬∃ Lcond Rcond C, Nonempty (LocalRule (Lcond, Rcond) C) ∧ Lcond ⊆ LR.1 ∧ Rcond ⊆ LR.2
⊢ Nonempty (LocalTableau LR)