Title
Model theory of monadic predicate logic with the infinity quantifier
Abstract
This paper establishes model-theoretic properties of $$\texttt {M} \texttt {E} ^{\infty }$$ , a variation of monadic first-order logic that features the generalised quantifier $$\exists ^\infty $$ (‘there are infinitely many’). We will also prove analogous versions of these results in the simpler setting of monadic first-order logic with and without equality ( $$\texttt {M} \texttt {E} $$ and $$\texttt {M} $$ , respectively). For each logic $$\texttt {L} \in \{ \texttt {M} , \texttt {M} \texttt {E} , \texttt {M} \texttt {E} ^{\infty }\}$$ we will show the following. We provide syntactically defined fragments of $$\texttt {L} $$ characterising four different semantic properties of $$\texttt {L} $$ -sentences: (1) being monotone and (2) (Scott) continuous in a given set of monadic predicates; (3) having truth preserved under taking submodels or (4) being truth invariant under taking quotients. In each case, we produce an effectively defined map that translates an arbitrary sentence $$\varphi $$ to a sentence $$\varphi ^\mathsf{p}$$ belonging to the corresponding syntactic fragment, with the property that $$\varphi $$ is equivalent to $$\varphi ^\mathsf{p}$$ precisely when it has the associated semantic property. As a corollary of our developments, we obtain that the four semantic properties above are decidable for $$\texttt {L} $$ -sentences.
Year
DOI
Venue
2018
10.1007/s00153-021-00797-0
Archive for Mathematical Logic
Keywords
Field
DocType
Monadic first-order logic, Generalised quantifier, Infinity quantifier, Characterisation theorem, Preservation theorem, Continuity, 03C80, 03C40
Discrete mathematics,Modulo,Quotient,Infinity,Decidability,Invariant (mathematics),Model theory,Predicate logic,Mathematics,Monotone polygon
Journal
Volume
Issue
ISSN
61
3
0933-5846
Citations 
PageRank 
References 
0
0.34
1
Authors
4
Name
Order
Citations
PageRank
Facundo Carreiro1124.09
Alessandro Facchini2359.47
Yde Venema360965.12
Fabio Zanasi411013.89