Description
Forcing: technique to expand universe V to V[G] by adjoining a generic object G. Forcing poset (P,≤,1); generic filter G; P-names; interpretation val(u,G); M[G]. Forcing relation p ⊩ φ. Coherence, definability, truth. Cohen forcing (Fin(S,2)).
Source: Wikipedia; Cohen (1963)
Dependency Flowchart
Note: Arrows mean "depends on". Assumes Charts 1–3.
graph TD
ZFC["ZFC\n(Charts 1–3)"]
DefPoset["Def: Forcing poset\n(P,≤,1) preorder, splitting"]
DefGeneric["Def: Generic filter\nG ⊆ P, dense meet"]
DefNames["Def: P-names\nV^P = ⋃ Name(α)"]
DefVal["Def: Interpretation\nval(u,G)"]
DefCheck["Def: Check names\nx̌"]
DefForce["Def: Forcing relation\np ⊩ φ"]
T1["Thm: M[G] ⊨ ZFC\nM[G] is model"]
T2["Thm: Coherence\nq≤p, p⊩φ ⇒ q⊩φ"]
T3["Thm: Definability\n⊩ definable in M"]
T4["Thm: Truth\nM[G]⊨φ iff ∃p∈G p⊩φ"]
T5["Thm: Rasiowa-Sikorski\nG exists for countable M"]
ExCohen["Ex: Cohen forcing\nFin(S,2)"]
ZFC --> DefPoset
DefPoset --> DefGeneric
DefPoset --> DefNames
DefNames --> DefVal
DefVal --> DefCheck
DefGeneric --> DefVal
DefVal --> DefForce
DefForce --> T1
DefForce --> T2
DefForce --> T3
DefForce --> T4
DefGeneric --> T5
DefPoset --> ExCohen
classDef axiom fill:#ff6b6b,color:#fff,stroke:#c0392b
classDef definition fill:#b197fc,color:#fff,stroke:#9775fa
classDef theorem fill:#51cf66,color:#fff,stroke:#40c057
class ZFC axiom
class DefPoset,DefGeneric,DefNames,DefVal,DefCheck,DefForce,ExCohen definition
class T1,T2,T3,T4,T5 theorem
Color Scheme
Red
Foundation (ZFC)
Foundation (ZFC)
Blue
Definitions
Definitions
Teal
Theorems
Theorems
Process Statistics
- Nodes: 17
- Edges: 19
- Axioms: 1
- Definitions: 7
- Theorems: 5