Definition
A property of a formal logic or theory stating that every sentence or formula that is satisfiable (has a model) has a finite model.
Principle
Principle
Restrict satisfiability to finite structures: if a formula can be realized at all, it can be realized in some finite structure; often used to link semantics to algorithmic checks by searching finite domains.
Demonstration
Demonstration
Many modal logics enjoy the property because filtration constructs a finite Kripke model from any satisfiable formula; concretely, a satisfiable modal formula can be shown to have a finite frame validating it.
Misapplication
Misapplication
Assuming that the finite model property implies completeness or decidability for arbitrary theories — FMP helps decidability in many cases but does not guarantee it without effective axiomatization or enumerability.
Consequence
Consequence
When present and the language/axioms are effectively enumerable, one typically obtains decidability by searching finite models; FMP also restricts possible countermodels to a finite search space.
Reversal
Reversal
The opposite situation is the infinite model property: there exist satisfiable formulas that admit only infinite models, so no finite structure realizes them.
Boundary
Boundary
Applies to logics or theories and their satisfiable sentences; it depends on the signature and allowed models (e.g., relational vs. functional signatures) and is not a statement about particular finite structures or counting models of bounded size.
Semantic Tension
Semantic Tension
Tension exists between finite satisfiability (existence of finite models) and general satisfiability (existence of arbitrary models); a logic can be satisfiable without FMP if realizations require infinite constructions.
Synthesis
Synthesis
Finite Model Property is the specification that satisfiability can always be witnessed by finite structures; it organizes semantic search procedures and sits between abstract satisfiability and effective decidability by constraining countermodels to finite domains.