Parameter: λ12 Identified

Algebraic Equations:

σ11λ1212

Single Door Criterion:

{1} ⊥ {2} | {}

Parameter: λ23 Identified

Algebraic Equations:

σ24λ2334

Instrumental Variable:

4 | {}

Parameter: ω11 Identified

Algebraic Equations:

1111

Parameter: ω13 Identified

Algebraic Equations:

13σ2412σ3424ω13

Parameter: ω14 Identified

Algebraic Equations:

1414

Parameter: ω22 Identified

Algebraic Equations:

σ12211σ2211ω22

Parameter: ω23 Identified

Algebraic Equations:

σ12σ13σ2411σ23σ24122σ3411σ22σ3411σ24ω23

Parameter: ω24 Identified

Algebraic Equations:

σ12σ1411σ2411ω24

Parameter: ω33 Identified

Algebraic Equations:

242σ33+2σ23σ24σ3422σ342242ω33

Parameter: ω44 Identified

Algebraic Equations:

4444

Total Effect of X1 on X3: λ12λ23 Identified

Each Parameter Identified

Vanishing Ideal

Zero Vanishing Ideal