Parameter: λ12 Identified

Algebraic Equations:

σ14λ1224,
23σ2412σ34λ12,
13σ2411σ34λ12

Instrumental Variable:

4 | {}

Parameter: λ13 Identified

Algebraic Equations:

σ14λ1334,
σ12λ1323,
σ11λ1313

Single Door Criterion:

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

Instrumental Variable:

2 | {}
2 | {4}
4 | {}
4 | {2}

Parameter: ω11 Identified

Algebraic Equations:

1111

Parameter: ω12 Identified

Algebraic Equations:

σ13σ2412σ3434ω12,
12σ1411σ2414ω12

Parameter: ω14 Identified

Algebraic Equations:

1414

Parameter: ω22 Identified

Algebraic Equations:

13σ24214σ22σ34+2σ12σ24σ3414σ34ω22,
142σ22+2σ12σ14σ2411σ242142ω22,
13σ23σ242+2σ12σ23σ24σ3412σ22σ34212σ342ω22,
132σ242+2σ11σ23σ24σ3411σ22σ34211σ342ω22

Parameter: ω33 Identified

Algebraic Equations:

14σ3313σ3414ω33,
σ13σ2312σ3312ω33,
σ13211σ3311ω33

Parameter: ω44 Identified

Algebraic Equations:

4444

Vanishing Ideal


Constraint Set:

σ14σ2312σ34,
σ13σ1411σ34,
σ12σ1311σ23

All constraints are determinantal

Trek-separation:

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