Parameter: λ₁₂ Identified

Algebraic Equations:

σ₁₃λ₁₂-σ₂₃,
σ₁₁λ₁₂-σ₁₂

Single Door Criterion:

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

Instrumental Variable:

3 | {}
3 | {4}

Parameter: λ₁₃ Identified

Algebraic Equations:

σ₁₂λ₁₃-σ₂₃,
σ₁₁λ₁₃-σ₁₃

Single Door Criterion:

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

Instrumental Variable:

2 | {}
2 | {4}

Parameter: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₂₂ Identified

Algebraic Equations:

-σ₁₃σ₂₂+σ₁₂σ₂₃+σ₁₃ω₂₂,
σ₁₂²-σ₁₁σ₂₂+σ₁₁ω₂₂

Parameter: ω₃₃ Identified

Algebraic Equations:

σ₁₃σ₂₃-σ₁₂σ₃₃+σ₁₂ω₃₃,
σ₁₃²-σ₁₁σ₃₃+σ₁₁ω₃₃

Parameter: ω₄₄ Identified

Algebraic Equations:

-σ₄₄+ω₄₄

Vanishing Ideal

Constraint Set:

σ₃₄,
σ₂₄,
σ₁₄,
σ₁₂σ₁₃-σ₁₁σ₂₃

All constraints are determinantal

Trek-separation:

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