Parameter: λ13 Identified

Algebraic Equations:

σ11λ1313

Single Door Criterion:

{1} ⊥ {3} | {}

Parameter: λ34 Identified

Algebraic Equations:

σ23λ3424

Instrumental Variable:

2 | {}

Parameter: ω11 Identified

Algebraic Equations:

1111

Parameter: ω12 Identified

Algebraic Equations:

1212

Parameter: ω14 Identified

Algebraic Equations:

14σ2313σ2423ω14

Parameter: ω22 Identified

Algebraic Equations:

2222

Parameter: ω23 Identified

Algebraic Equations:

σ12σ1311σ2311ω23

Parameter: ω33 Identified

Algebraic Equations:

σ13211σ3311ω33

Parameter: ω34 Identified

Algebraic Equations:

σ13σ14σ23132σ2411σ24σ3311σ23σ3411σ23ω34

Parameter: ω44 Identified

Algebraic Equations:

242σ33+2σ23σ24σ34232σ44232ω44

Total Effect of X1 on X4: λ13λ34 Identified

Each Parameter Identified

Vanishing Ideal

Zero Vanishing Ideal