Parameter: λ₁₂ Identified

Algebraic Equations:

σ₁₄λ₁₂-σ₂₄

Instrumental Variable:

3 | {4}
4 | {}
4 | {3}

Parameter: λ₃₄ Identified

Algebraic Equations:

σ₃₃λ₃₄-σ₃₄

Single Door Criterion:

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

Parameter: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₁₂ Identified

Algebraic Equations:

-σ₁₂σ₁₄+σ₁₁σ₂₄+σ₁₄ω₁₂

Parameter: ω₁₄ Identified

Algebraic Equations:

-σ₁₄+ω₁₄

Parameter: ω₂₂ Identified

Algebraic Equations:

-σ₁₄²σ₂₂+2σ₁₂σ₁₄σ₂₄-σ₁₁σ₂₄²+σ₁₄²ω₂₂

Parameter: ω₃₃ Identified

Algebraic Equations:

-σ₃₃+ω₃₃

Parameter: ω₄₄ Identified

Algebraic Equations:

σ₃₄²-σ₃₃σ₄₄+σ₃₃ω₄₄

Vanishing Ideal

Constraint Set:

σ₂₃,
σ₁₃

All constraints are determinantal

Trek-separation:

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