This shows you the differences between two versions of the page.
Both sides previous revision Previous revision | Last revision Both sides next revision | ||
exam [2011/07/19 14:00] 131.246.18.253 [Calculi] |
exam [2011/07/19 14:16] 131.246.18.253 [Calculi] |
||
---|---|---|---|
Line 56: | Line 56: | ||
* A deductive system is sound if all provable formulas are valid. It is complete if all valid formulas are provable. | * A deductive system is sound if all provable formulas are valid. It is complete if all valid formulas are provable. | ||
* Validity is a semantic property ($A \models B$), while provability a syntactic one ($A \vdash B$). So, in other words we have: | * Validity is a semantic property ($A \models B$), while provability a syntactic one ($A \vdash B$). So, in other words we have: | ||
- | * Soundness: $A \vdash B \rightarrow A \models B$ | + | * Soundness: $A \vdash B \longrightarrow A \models B$ |
- | * Completeness: $A \models B \rightarrow A \vdash B$ | + | * Completeness: $A \models B \longrightarrow A \vdash B$ |
:?: What are the advantages/disadvantages of the Hilbert calculus compared to the Gentzen calculus. | :?: What are the advantages/disadvantages of the Hilbert calculus compared to the Gentzen calculus. |