• 1 Overview ▶
    • 1.1 What Has Been Built
    • 1.2 How To Read The Blueprint
    • 1.3 The Current Frontier
    • 1.4 Formalization Note
  • 2 First-Order Logic Core ▶
    • 2.1 Languages, Terms, And Formulas
    • 2.2 Derivability
    • 2.3 Structures And Satisfaction
    • 2.4 Sentences, Theories, And Bounded Syntax
    • 2.5 A Model-Theoretic Example
    • 2.6 Formalization Note
  • 3 Compactness And Completion ▶
    • 3.1 Compactness As A Finitary Principle
    • 3.2 Compactness For Theories
    • 3.3 Controlled Unions
    • 3.4 Chains Of Consistent Extensions
    • 3.5 Maximal Consistent Extensions
    • 3.6 Why This Matters Later
    • 3.7 Formalization Note
  • 4 Colimits And Language Extensions ▶
    • 4.1 Directed Systems And Their Colimits
    • 4.2 Maps Of Languages
    • 4.3 Symbol Support And Filtered Languages
    • 4.4 Proof Transport And Reducts
    • 4.5 Reflection Along Injective Language Maps
    • 4.6 Fresh Constants And Generalization
    • 4.7 Role In Henkinization
    • 4.8 Formalization Note
  • 5 Henkinization ▶
    • 5.1 Adjoining Witness Constants In One Step
    • 5.2 Iterating The Construction
    • 5.3 The Infinite Henkin Language
    • 5.4 Finite-Stage Representatives
    • 5.5 Witness Sentences And Enough Constants
    • 5.6 The One-Step Theory Extension
    • 5.7 Consistency Of One Henkin Step
    • 5.8 Passing To The Limit Theory
    • 5.9 Enough Constants In The Limit
    • 5.10 Complete Henkin Extensions
    • 5.11 Present Boundary
    • 5.12 Formalization Note
  • 6 Status And Next Frontier ▶
    • 6.1 What The Current Port Delivers
    • 6.2 What Is Not Yet Present
    • 6.3 The Next Frontier
    • 6.4 How The Blueprint Should Grow
  • Dependency graph

Flypitch Lean 4

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  • 1 Overview
    • 1.1 What Has Been Built
    • 1.2 How To Read The Blueprint
    • 1.3 The Current Frontier
    • 1.4 Formalization Note
  • 2 First-Order Logic Core
    • 2.1 Languages, Terms, And Formulas
    • 2.2 Derivability
    • 2.3 Structures And Satisfaction
    • 2.4 Sentences, Theories, And Bounded Syntax
    • 2.5 A Model-Theoretic Example
    • 2.6 Formalization Note
  • 3 Compactness And Completion
    • 3.1 Compactness As A Finitary Principle
    • 3.2 Compactness For Theories
    • 3.3 Controlled Unions
    • 3.4 Chains Of Consistent Extensions
    • 3.5 Maximal Consistent Extensions
    • 3.6 Why This Matters Later
    • 3.7 Formalization Note
  • 4 Colimits And Language Extensions
    • 4.1 Directed Systems And Their Colimits
    • 4.2 Maps Of Languages
    • 4.3 Symbol Support And Filtered Languages
    • 4.4 Proof Transport And Reducts
    • 4.5 Reflection Along Injective Language Maps
    • 4.6 Fresh Constants And Generalization
    • 4.7 Role In Henkinization
    • 4.8 Formalization Note
  • 5 Henkinization
    • 5.1 Adjoining Witness Constants In One Step
    • 5.2 Iterating The Construction
    • 5.3 The Infinite Henkin Language
    • 5.4 Finite-Stage Representatives
    • 5.5 Witness Sentences And Enough Constants
    • 5.6 The One-Step Theory Extension
    • 5.7 Consistency Of One Henkin Step
    • 5.8 Passing To The Limit Theory
    • 5.9 Enough Constants In The Limit
    • 5.10 Complete Henkin Extensions
    • 5.11 Present Boundary
    • 5.12 Formalization Note
  • 6 Status And Next Frontier
    • 6.1 What The Current Port Delivers
    • 6.2 What Is Not Yet Present
    • 6.3 The Next Frontier
    • 6.4 How The Blueprint Should Grow