コンパクト有向シーケント計算の規則
いくつかの事例、シーケント推論図の形式:
[Γ→Δ],[Π→Σ]⇒Γ,Π→Δ,Σ Γ→Δ Π→Σ ===============(×) Γ,Π→Δ,Σ [Γ→Δ,A], [A,Π→Σ]⇒[Γ,Π→Δ,Σ] (A has ↓) Γ→Δ,A A,Π→Σ ====================(\↓A) Γ,Π→Δ,Σ [Γ→Δ,A],[Π→A*,Σ]⇒[Γ,Π→Δ,Σ] (A has ↓) Γ→Δ,A Π→A*,Σ ======================(∪→A) Γ,Π→Δ,Σ
自然演繹証明図の変形として描くと:
[Γ→Δ],[Π→Σ]⇒Γ,Π→Δ,Σ before Γ Π --- --- : : : : --- --- Δ Σ after Γ,Π ------ : : ------ Δ,Σ [Γ→Δ,A], [A,Π→Σ]⇒[Γ,Π→Δ,Σ] before (A has ↓) Γ A,Π ---- ---- : : : : ---- ---- Δ,A Σ after Γ,Π ----- : : ----- Δ,Σ [Γ→Δ,A],[Π→A*,Σ]⇒[Γ,Π→Δ,Σ] before (A has ↓) Γ Π --- --- : : : : ---- ----- Δ,A A*,Σ after Γ,Π ----- : : ----- Δ,Σ
(\↓A)の配置をソレらしくすると:
[Γ→Δ,A], [A,Π→Σ]⇒[Γ,Π→Δ,Σ] before (A has ↓) Γ : --- : : : : : ---- : Δ,A : : A,Π : ---- : : : : : ---- : Σ after Γ,Π ----- : : ----- Δ,Σ