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Single Idea 10756

[filed under theme 5. Theory of Logic / J. Model Theory in Logic / 1. Logical Models ]

Full Idea

A standard model is a set of objects called the 'domain', and an interpretation function, assigning objects in the domain to names, subsets to predicate letters, subsets of the Cartesian product of the domain with itself to binary relation symbols etc.

Clarification

The Cartesian Product produces all permutations of pairs of objects

Gist of Idea

A model is a domain, and an interpretation assigning objects, predicates, relations etc.

Source

Marcus Rossberg (First-order Logic, 2nd-order, Completeness [2004], §3)


A Reaction

The model actually specifies which objects have which predicates, and which objects are in which relations. Tarski's account of truth in terms of 'satisfaction' seems to be just a description of those pre-decided facts.


The 10 ideas from 'First-order Logic, 2nd-order, Completeness'

Second-order logic needs the sets, and its consequence has epistemological problems [Rossberg]
Logical consequence is intuitively semantic, and captured by model theory [Rossberg]
Γ |- S says S can be deduced from Γ; Γ |= S says a good model for Γ makes S true [Rossberg]
In proof-theory, logical form is shown by the logical constants [Rossberg]
If models of a mathematical theory are all isomorphic, it is 'categorical', with essentially one model [Rossberg]
A model is a domain, and an interpretation assigning objects, predicates, relations etc. [Rossberg]
There are at least seven possible systems of semantics for second-order logic [Rossberg]
Henkin semantics has a second domain of predicates and relations (in upper case) [Rossberg]
A deductive system is only incomplete with respect to a formal semantics [Rossberg]
Completeness can always be achieved by cunning model-design [Rossberg]