Combining Texts
Ideas for
'fragments/reports', 'Dispositions and Powers' and 'Alfred Tarski: life and logic'
expand these ideas
|
start again
|
choose
another area for these texts
display all the ideas for this combination of texts
9 ideas
5. Theory of Logic / B. Logical Consequence / 5. Modus Ponens
8078
|
Modus ponens is one of five inference rules identified by the Stoics [Chrysippus, by Devlin]
|
5. Theory of Logic / D. Assumptions for Logic / 2. Excluded Middle
6023
|
Every proposition is either true or false [Chrysippus, by Cicero]
|
5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models
10158
|
A structure is a 'model' when the axioms are true. So which of the structures are models? [Feferman/Feferman]
|
10162
|
Tarski and Vaught established the equivalence relations between first-order structures [Feferman/Feferman]
|
5. Theory of Logic / J. Model Theory in Logic / 3. Löwenheim-Skolem Theorems
10160
|
Löwenheim-Skolem says if the sentences are countable, so is the model [Feferman/Feferman]
|
10159
|
Löwenheim-Skolem Theorem, and Gödel's completeness of first-order logic, the earliest model theory [Feferman/Feferman]
|
5. Theory of Logic / K. Features of Logics / 4. Completeness
10161
|
If a sentence holds in every model of a theory, then it is logically derivable from the theory [Feferman/Feferman]
|
5. Theory of Logic / K. Features of Logics / 7. Decidability
10156
|
'Recursion theory' concerns what can be solved by computing machines [Feferman/Feferman]
|
10155
|
Both Principia Mathematica and Peano Arithmetic are undecidable [Feferman/Feferman]
|