Parameter: λ₁₄ Identified

Algebraic Equations:

σ₁₃λ₁₄-σ₃₄,
σ₁₁λ₁₄-σ₁₄

Single Door Criterion:

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

Instrumental Variable:

3 | {}
3 | {2}

Parameter: λ₂₄ Identified

Algebraic Equations:

σ₂₂λ₂₄-σ₂₄

Single Door Criterion:

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

Parameter: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₁₃ Identified

Algebraic Equations:

-σ₁₃+ω₁₃

Parameter: ω₂₂ Identified

Algebraic Equations:

-σ₂₂+ω₂₂

Parameter: ω₃₃ Identified

Algebraic Equations:

-σ₃₃+ω₃₃

Parameter: ω₄₄ Identified

Algebraic Equations:

σ₁₃σ₂₄²+σ₁₄σ₂₂σ₃₄-σ₁₃σ₂₂σ₄₄+σ₁₃σ₂₂ω₄₄,
σ₁₄²σ₂₂+σ₁₁σ₂₄²-σ₁₁σ₂₂σ₄₄+σ₁₁σ₂₂ω₄₄

Vanishing Ideal

Constraint Set:

σ₂₃,
σ₁₂,
σ₁₃σ₁₄-σ₁₁σ₃₄

All constraints are determinantal

Trek-separation:

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