Parameter: λ₁₂ Identified

Algebraic Equations:

σ₁₁λ₁₂-σ₁₂

Single Door Criterion:

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

Parameter: λ₃₄ Identified

Algebraic Equations:

σ₂₃λ₃₄-σ₂₄

Instrumental Variable:

1 | {2}
2 | {}
2 | {1}

Parameter: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₂₂ Identified

Algebraic Equations:

σ₁₂²-σ₁₁σ₂₂+σ₁₁ω₂₂

Parameter: ω₂₃ Identified

Algebraic Equations:

-σ₂₃+ω₂₃

Parameter: ω₃₃ Identified

Algebraic Equations:

-σ₃₃+ω₃₃

Parameter: ω₃₄ Identified

Algebraic Equations:

σ₂₄σ₃₃-σ₂₃σ₃₄+σ₂₃ω₃₄

Parameter: ω₄₄ Identified

Algebraic Equations:

-σ₂₄²σ₃₃+2σ₂₃σ₂₄σ₃₄-σ₂₃²σ₄₄+σ₂₃²ω₄₄

Vanishing Ideal

Constraint Set:

σ₁₄,
σ₁₃

All constraints are determinantal

Trek-separation:

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