Parameter: λ₁₂

Parameter: λ₁₃ Identified

Algebraic Equations:

σ₁₄σ₂₂λ₁₃-σ₁₂σ₂₄λ₁₃+σ₂₃σ₂₄-σ₂₂σ₃₄,
σ₁₂²λ₁₃-σ₁₁σ₂₂λ₁₃+σ₁₃σ₂₂-σ₁₂σ₂₃

Single Door Criterion:

{1} ⊥ {3} | {2}
{1} ⊥ {3} | {2,4}

Instrumental Variable:

4 | {2}

Parameter: λ₁₄ Identified

Algebraic Equations:

σ₁₃λ₁₄-σ₃₄,
σ₁₂λ₁₄-σ₂₄,
σ₁₁λ₁₄-σ₁₄

Single Door Criterion:

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

Instrumental Variable:

2 | {}
2 | {3}
3 | {}
3 | {2}

Parameter: λ₂₃ Identified

Algebraic Equations:

σ₁₄σ₂₂λ₂₃-σ₁₄σ₂₃-σ₁₂σ₂₄λ₂₃+σ₁₂σ₃₄,
σ₁₂²λ₂₃-σ₁₂σ₁₃-σ₁₁σ₂₂λ₂₃+σ₁₁σ₂₃

Single Door Criterion:

{2} ⊥ {3,4} | {1}
{2} ⊥ {3} | {1,4}

Parameter: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₁₂

Parameter: ω₂₂

Parameter: ω₃₃ Identified

Algebraic Equations:

σ₁₄σ₂₃²-σ₁₄σ₂₂σ₃₃+σ₁₂σ₂₄σ₃₃+σ₁₃σ₂₂σ₃₄-2σ₁₂σ₂₃σ₃₄+σ₁₄σ₂₂ω₃₃-σ₁₂σ₂₄ω₃₃,
-σ₁₃²σ₂₂+2σ₁₂σ₁₃σ₂₃-σ₁₁σ₂₃²-σ₁₂²σ₃₃+σ₁₁σ₂₂σ₃₃+σ₁₂²ω₃₃-σ₁₁σ₂₂ω₃₃

Parameter: ω₄₄ Identified

Algebraic Equations:

σ₁₄σ₃₄-σ₁₃σ₄₄+σ₁₃ω₄₄,
σ₁₄σ₂₄-σ₁₂σ₄₄+σ₁₂ω₄₄,
σ₁₄²-σ₁₁σ₄₄+σ₁₁ω₄₄

Total Effect of X₁ on X₃: λ₁₂λ₂₃+λ₁₃

Path-specific Effect of X₁ on X₃: λ₁₂λ₂₃

Vanishing Ideal

Constraint Set:

σ₁₃σ₂₄-σ₁₂σ₃₄,
σ₁₃σ₁₄-σ₁₁σ₃₄,
σ₁₂σ₁₄-σ₁₁σ₂₄

All constraints are determinantal

Trek-separation:

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