Parameter: λ₁₃ Identified

Algebraic Equations:

σ₁₄λ₁₃-σ₃₄,
σ₁₁λ₁₃-σ₁₃

Single Door Criterion:

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

Instrumental Variable:

2 | {4}
4 | {}
4 | {2}

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: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₂₂ Identified

Algebraic Equations:

-σ₂₂+ω₂₂

Parameter: ω₂₄ Identified

Algebraic Equations:

-σ₂₄+ω₂₄

Parameter: ω₃₃ Identified

Algebraic Equations:

-σ₁₄σ₃₃+σ₁₃σ₃₄+σ₁₄ω₃₃,
σ₁₃²-σ₁₁σ₃₃+σ₁₁ω₃₃

Parameter: ω₄₄ Identified

Algebraic Equations:

σ₁₄σ₃₄-σ₁₃σ₄₄+σ₁₃ω₄₄,
σ₁₄²-σ₁₁σ₄₄+σ₁₁ω₄₄

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},{})
{1,3} ⊥ {1,2,4} | ({},{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})