The relative strength of two systems of formal logic can be defined via model theory. Specifically, a logic [math]\displaystyle{ \alpha }[/math] is said to be as strong as a logic [math]\displaystyle{ \beta }[/math] if every elementary class in [math]\displaystyle{ \beta }[/math] is an elementary class in [math]\displaystyle{ \alpha }[/math].[1]
See also
- Abstract logic
- Lindström's theorem
References
- ↑ Heinz-Dieter Ebbinghaus Extended logics: the general framework in K. J. Barwise and S. Feferman, editors, Model-theoretic logics, 1985 ISBN 0-387-90936-2 page 43
Mathematical logic |
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| General |
- Formal language
- Formation rule
- Formal proof
- Formal semantics
- Well-formed formula
- Set
- Element
- Class
- Classical logic
- Axiom
- Rule of inference
- Relation
- Theorem
- Logical consequence
- Type theory
- Symbol
- Syntax
- Theory
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| Systems |
- Formal system
- Deductive system
- Axiomatic system
- Hilbert style systems
- Natural deduction
- Sequent calculus
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| Traditional logic |
- Proposition
- Inference
- Argument
- Validity
- Cogency
- Syllogism
- Square of opposition
- Venn diagram
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Propositional calculus and Boolean logic |
- Boolean functions
- Propositional calculus
- Propositional formula
- Logical connectives
- Truth tables
- Many-valued logic
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| Predicate logic |
- First-order
- Quantifiers
- Predicate
- Second-order
- Monadic predicate calculus
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| Naive set theory |
- Set
- Empty set
- Element
- Enumeration
- Extensionality
- Finite set
- Infinite set
- Subset
- Power set
- Countable set
- Uncountable set
- Recursive set
- Domain
- Codomain
- Image
- Map
- Function
- Relation
- Ordered pair
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| Set theory |
- Foundations of mathematics
- Zermelo–Fraenkel set theory
- Axiom of choice
- General set theory
- Kripke–Platek set theory
- Von Neumann–Bernays–Gödel set theory
- Morse–Kelley set theory
- Tarski–Grothendieck set theory
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| Model theory |
- Model
- Interpretation
- Non-standard model
- Finite model theory
- Truth value
- Validity
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| Proof theory |
- Formal proof
- Deductive system
- Formal system
- Theorem
- Logical consequence
- Rule of inference
- Syntax
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Computability theory |
- Recursion
- Recursive set
- Recursively enumerable set
- Decision problem
- Church–Turing thesis
- Computable function
- Primitive recursive function
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 | Original source: https://en.wikipedia.org/wiki/Strength (mathematical logic). Read more |