Parameter: λ₂₃

Parameter: λ₃₄ Identified

Algebraic Equations:

σ₃₃λ₃₄-σ₃₄,
σ₂₃λ₃₄-σ₂₄

Single Door Criterion:

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

Instrumental Variable:

2 | {}
2 | {1}

Parameter: ω₁₁ Identified

Algebraic Equations:

-σ₁₁+ω₁₁

Parameter: ω₂₂ Identified

Algebraic Equations:

-σ₂₂+ω₂₂

Parameter: ω₂₃

Parameter: ω₃₃

Parameter: ω₄₄ Identified

Algebraic Equations:

σ₃₄²-σ₃₃σ₄₄+σ₃₃ω₄₄,
σ₂₄σ₃₄-σ₂₃σ₄₄+σ₂₃ω₄₄

Total Effect of X₂ on X₄: λ₂₃λ₃₄

Vanishing Ideal

Constraint Set:

σ₁₄,
σ₁₃,
σ₁₂,
σ₂₄σ₃₃-σ₂₃σ₃₄

All constraints are determinantal

Trek-separation:

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