Parameter: λ₁₃ Identified

Algebraic Equations:

σ₁₄λ₁₃-σ₃₄,
σ₁₁λ₁₃-σ₁₃

Single Door Criterion:

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

Instrumental Variable:

4 | {}
4 | {2}

Parameter: λ₁₄

Parameter: λ₂₃ Identified

Algebraic Equations:

σ₂₂λ₂₃-σ₂₃

Single Door Criterion:

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

Parameter: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₁₄

Parameter: ω₂₂ Identified

Algebraic Equations:

-σ₂₂+ω₂₂

Parameter: ω₃₃ Identified

Algebraic Equations:

σ₁₄σ₂₃²-σ₁₄σ₂₂σ₃₃+σ₁₃σ₂₂σ₃₄+σ₁₄σ₂₂ω₃₃,
σ₁₃²σ₂₂+σ₁₁σ₂₃²-σ₁₁σ₂₂σ₃₃+σ₁₁σ₂₂ω₃₃

Parameter: ω₄₄

Vanishing Ideal

Constraint Set:

σ₂₄,
σ₁₂,
σ₁₃σ₁₄-σ₁₁σ₃₄

All constraints are determinantal

Trek-separation:

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