Parameter: λ₁₂

Parameter: λ₂₃ Identified

Algebraic Equations:

σ₁₂λ₂₃-σ₁₃

Instrumental Variable:

1 | {}

Parameter: λ₂₄ Identified

Algebraic Equations:

σ₂₃λ₂₄-σ₃₄,
σ₂₂λ₂₄-σ₂₄,
σ₁₂λ₂₄-σ₁₄

Single Door Criterion:

{2} ⊥ {4} | {}
{2} ⊥ {4} | {3}
{2} ⊥ {4} | {1}
{2} ⊥ {4} | {1,3}

Instrumental Variable:

1 | {}
1 | {3}
3 | {}
3 | {1}

Parameter: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₁₂

Parameter: ω₂₂

Parameter: ω₂₃ Identified

Algebraic Equations:

σ₁₃σ₂₄-σ₁₂σ₃₄+σ₁₄ω₂₃,
σ₁₃σ₂₂-σ₁₂σ₂₃+σ₁₂ω₂₃

Parameter: ω₃₃ Identified

Algebraic Equations:

-σ₁₃²σ₂₄-σ₁₂σ₁₄σ₃₃+2σ₁₂σ₁₃σ₃₄+σ₁₂σ₁₄ω₃₃,
-σ₁₃²σ₂₂+2σ₁₂σ₁₃σ₂₃-σ₁₂²σ₃₃+σ₁₂²ω₃₃

Parameter: ω₄₄ Identified

Algebraic Equations:

σ₂₄σ₃₄-σ₂₃σ₄₄+σ₂₃ω₄₄,
σ₂₄²-σ₂₂σ₄₄+σ₂₂ω₄₄,
σ₁₄σ₂₄-σ₁₂σ₄₄+σ₁₂ω₄₄

Total Effect of X₁ on X₃: λ₁₂λ₂₃

Total Effect of X₁ on X₄: λ₁₂λ₂₄

Vanishing Ideal

Constraint Set:

σ₂₃σ₂₄-σ₂₂σ₃₄,
σ₁₄σ₂₃-σ₁₂σ₃₄,
σ₁₄σ₂₂-σ₁₂σ₂₄

All constraints are determinantal

Trek-separation:

{1,2,3} ⊥ {2,4} | ({},{2})
{1,2,3} ⊥ {2,3,4} | ({},{2,3})
{1,2,3} ⊥ {1,2,4} | ({},{1,2})