Parameter: λ₁₃ Identified

Algebraic Equations:

σ₁₄λ₁₃-σ₃₄

Instrumental Variable:

4 | {}
4 | {2}

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: ω₁₃ Identified

Algebraic Equations:

-σ₁₃σ₁₄+σ₁₁σ₃₄+σ₁₄ω₁₃

Parameter: ω₁₄ Identified

Algebraic Equations:

-σ₁₄+ω₁₄

Parameter: ω₂₂ Identified

Algebraic Equations:

-σ₂₂+ω₂₂

Parameter: ω₃₃ Identified

Algebraic Equations:

σ₁₄²σ₂₃²-σ₁₄²σ₂₂σ₃₃+2σ₁₃σ₁₄σ₂₂σ₃₄-σ₁₁σ₂₂σ₃₄²+σ₁₄²σ₂₂ω₃₃

Parameter: ω₄₄ Identified

Algebraic Equations:

-σ₄₄+ω₄₄

Vanishing Ideal

Constraint Set:

σ₂₄,
σ₁₂

All constraints are determinantal

Trek-separation:

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