User:IssaRice/Computability and logic/Semantic completeness: Difference between revisions
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Semantic completeness is sometimes written as: if <math>\Sigma \models \phi</math>, then <math>\Sigma \vdash \phi</math>. | Semantic completeness is sometimes written as: if <math>\Sigma \models \phi</math>, then <math>\Sigma \vdash \phi</math>. | ||
Semantic completeness is the completeness that is the topic of Godel's completeness theorem. | |||
Semantic completeness differs from [[../Negation completeness|negation completeness]]. | Semantic completeness differs from [[../Negation completeness|negation completeness]]. | ||
Revision as of 05:41, 21 December 2018
Semantic completeness is sometimes written as: if , then .
Semantic completeness is the completeness that is the topic of Godel's completeness theorem.
Semantic completeness differs from negation completeness.
Definition
I want to make sure all these definitions are saying the same thing, so let me list some from several textbooks so I can explicitly compare.
Smith's definition: a logic is semantically complete iff for any set of wffs and any sentence , if then .[1]
Leary/Kristiansen's definition: A deductive system consisting of logical axioms and a collection of rules of inference is said to be complete iff for every set of nonlogical axioms and every -formula , if , then .[2]