Finite Embeddability Property Research Articles

Residuated Basic Logic

Residuated basic logic (RBL) is the logic of residuated basic algebras, which constitutes a conservative extension of basic propositional logic (BPL). The basic implication is a residual of a non-associative binary operator in RBL. The conservativity is shown by relational semantics. A Gentzen-style sequent calculus GRBL, which is an extension of the distributive full non-associative Lambek calculus, is established for residuated basic logic. The calculus GRBL admits the mix-elimination, subformula, and disjunction properties. Moreover, the class of all residuated basic algebras has the finite embeddability property. The consequence relation of GRBL is decidable.

MOST SIMPLE EXTENSIONS OF ARE UNDECIDABLE

AbstractAll known structural extensions of the substructural logic $\textbf{FL}_{\textbf{e}}$ , the Full Lambek calculus with exchange/commutativity (corresponding to subvarieties of commutative residuated lattices axiomatized by $\{\vee , \cdot , 1\}$ -equations), have decidable theoremhood; in particular all the ones defined by knotted axioms enjoy strong decidability properties (such as the finite embeddability property). We provide infinitely many such extensions that have undecidable theoremhood, by encoding machines with undecidable halting problem. An even bigger class of extensions is shown to have undecidable deducibility problem (the corresponding varieties of residuated lattices have undecidable word problem); actually with very few exceptions, such as the knotted axioms and the other prespinal axioms, we prove that undecidability is ubiquitous. Known undecidability results for non-commutative extensions use an encoding that fails in the presence of commutativity, so and-branching counter machines are employed. Even these machines provide encodings that fail to capture proper extensions of commutativity, therefore we introduce a new variant that works on an exponential scale. The correctness of the encoding is established by employing the theory of residuated frames.

Join-completions of partially ordered algebras

We present a systematic study of join-extensions and join-completions of partially ordered algebras, which naturally leads to a refined and simplified treatment of fundamental results and constructions in the theory of ordered structures ranging from properties of the Dedekind–MacNeille completion to the proof of the finite embeddability property for a number of varieties of lattice-ordered algebras.

Structure theorems for idempotent residuated lattices

In this paper we study structural properties of residuated lattices that are idempotent as monoids. We provide descriptions of the totally ordered members of this class and obtain counting theorems for the number of finite algebras in various subclasses. We also establish the finite embeddability property for certain varieties generated by classes of residuated lattices that are conservative in the sense that monoid multiplication always yields one of its arguments. We then make use of a more symmetric version of Raftery’s characterization theorem for totally ordered commutative idempotent residuated lattices to prove that the variety generated by this class has the amalgamation property. Finally, we address an open problem in the literature by giving an example of a noncommutative variety of idempotent residuated lattices that has the amalgamation property.

The finite embeddability property for IP loops and local embeddability of groups into finite IP loops

We prove that the class of all loops with the inverse property (IP loops) has the Finite Embeddability Property (FEP). As a consequence, every group is locally embeddable into finite IP loops. The first one of these results is obtained as a consequence of a more general embeddability theorem, contributing to a list of problems posed by T. Evans in 1978, namely, that every finite partial IP loop can be embedded into a finite IP loop.

On the finite embeddability property for quantum B-algebras

Abstract After the establishment of the finite embeddability property for integral and commutative residuated ordered monoids by Blok and Van Alten in 2002, the finite embeddability property for some other types of residuated ordered algebraic structures have been extensively studied. The main purpose of this paper is to construct a finite quantale X̂F from a finite partial subalgebra F of an increasing quantum B-algebra X so that F can be embedded into X̂F , that is, the class of increasing quantum B-algebras has the finite embeddability property.

Variety generated by conical residuated lattice-ordered idempotent monoids

In this paper, we study the variety generated by conical idempotent residuated lattices. After obtaining some properties of conical idempotent residuated lattices, we establish a chain decomposition theorem for conical idempotent residuated lattices and give an equational basis for the variety. It is proved that the variety has the finite embeddability property. It is also proved that the semigroup reduct of a semiconical idempotent residuated lattice is a regular band.

Semilinear substructural logics with the finite embeddability property

Three semilinear substructural logics $${\mathbf{HpsUL}}_\omega ^*$$ , $${\mathbf{UL}}_\omega $$ and $${\mathbf{IUL}}_\omega $$ are constructed. Then the completeness of $${ \mathbf{UL}}_\omega $$ and $${\mathbf{IUL}}_\omega $$ with respect to classes of finite UL and IUL-algebras, respectively, is proved. Algebraically, non-integral $${\mathbf{UL}}_\omega $$ and $${\mathbf{IUL}}_\omega $$ -algebras have the finite embeddability property, which gives a characterization for finite UL and IUL-algebras.

Finite coverability property

In this article we present a new characterization of the class $${{\mathrm{HSP_U}}}(\mathcal {K})$$ using a condition analogous to the finite embeddability property.

The FEP for some varieties of fully distributive knotted residuated lattices

We prove the finite embeddability property for a wide range of varieties of fully distributive residuated lattices and FL-algebras. Part of the axiomatization is assumed to be a knotted inequality and some appropriate generalization of commutativity. The construction is based on distributive residuated frames and extends to subvarieties axiomatized by any division-free equation.

Distributive residuated frames and generalized bunched implication algebras

We show that all extensions of the (non-associative) Gentzen system for distributive full Lambek calculus by simple structural rules have the cut elimination property. Also, extensions by such rules that do not increase complexity have the finite model property, hence many subvarieties of the variety of distributive residuated lattices have decidable equational theories. For some other extensions, we prove the finite embeddability property, which implies the decidability of the universal theory, and we show that our results also apply to generalized bunched implication algebras. Our analysis is conducted in the general setting of residuated frames.

Varieties of BL-algebras I, revisited

In this paper, we explore some unexplored consequences of Agliano et al. (Studia Logica 87:73---98, 2007) and Agliano and Montagna (J Pure Appl Algebra 181:105---129, 2003) on varieties of BL-algebras and their hoop subreducts. The main topics are: generation by finite algebras, the finite embeddability property and varieties of finite index.

The finite embeddability property for noncommutative knotted extensions of RL

The finite embeddability property (FEP) for knotted extensions of residuated lattices holds under the assumption of commutativity, but fails in the general case. We identify weaker forms of the commutativity identity which ensure that the FEP holds. The results have applications outside of order algebra to non-classical logic, establishing the strong finite model property (SFMP) and the decidability for deductions, as well as to mathematical linguistics and automata theory, providing new conditions for recognizability of languages. Our proofs make use of residuated frames, developed in the context of algebraic proof theory.

The canonical FEP construction

A class K of algebras has the finite embeddability property (FEP) if every finite partial subalgebra of some member of K can be embedded into some finite member of K⁠. We prove the FEP for varieties of decreasing residuated lattice-ordered algebras using a construction based on the canonical extension. This construction produces a (generally) different finite member of the class from alternative FEP constructions for similar classes of algebras. Additionally, the constructed algebra is internally compact, in contrast to other FEP constructions. We give a description of the σ- and π-extensions of operations that do not rely on the notions of closed and open elements and we use this to obtain a syntactic description of a class of inequalities s≤t that are preserved by the construction.

The finite embeddability property for residuated groupoids

A very simple proof of the finite embeddability property for residuated distributive-lattice-ordered groupoids and some related classes of structures is presented. In particular, this gives an answer to the question, posed by Blok and van Alten, whether the class of residuated ordered groupoids has the property. The presented construction improves the computational-complexity upper bound of the universal theory of residuated distributive-lattice-ordered groupoids given by Buszkowski and Farulewski; for chains in the class, a tight bound is obtained.

Cayley’s and Holland’s Theorems for Idempotent Semirings and Their Applications to Residuated Lattices

We extend Cayley’s and Holland’s representation theorems to idempotent semirings and residuated lattices, and provide both functional and relational versions. Our analysis allows for extensions of the results to situations where conditions are imposed on the order relation of the representing structures. Moreover, we give a new proof of the finite embeddability property for the variety of integral residuated lattices and many of its subvarieties.

Residuated frames with applications to decidability

Residuated frames provide relational semantics for substructural logics and are a natural generalization of Kripke frames in intuitionistic and modal logic, and of phase spaces in linear logic. We explore the connection between Gentzen systems and residuated frames and illustrate how frames provide a uniform treatment for semantic proofs of cut-elimination, the finite model property and the finite embeddability property. We use our results to prove the decidability of the equational and/or universal theory of several varieties of residuated lattice-ordered groupoids, including the variety of involutive

Interpolation and FEP for logics of residuated algebras

A residuated algebra (RA) is a generalization of a residuated groupoid; instead of one basic binary operation · with residual operations \, /, it admits finitely many basic operations, and each n−ary basic operation is associated with n residual operations. A basic logical system for RAs was studied in e.g. [6, 8, 16, 15] under the name: Generalized Lambek Calculus GL. In this paper we study GL and its extensions in the form of sequent systems. We prove an interpolation property which allows to replace a substructure of the antecedent structure by a single formula in a provable sequent. Together with model constructions, based on nuclei [13], interpolation leads to proofs of Finite Embeddability Property of different classes of RAs, as e.g. all RAs, distributive lattice-ordered RAs, boolean RAs, Heyting RAs and double RAs.

Semiconic idempotent residuated structures

An idempotent residuated po-monoid is semiconic if it is a subdirect product of algebras in which the monoid identity is comparable with all other elements. It is proved that the quasivariety SCIP of all semiconic idempotent commutative residuated po-monoids is locally finite. The lattice-ordered members of this class form avariety SCIL, which is not locally finite, but it is proved that SCIL has the finite embeddability property (FEP). More generally, for every relative subvariety K of SCIP, the lattice-ordered members of K have the FEP. This gives a unified explanation of the strong finite model property for a range of logical systems. It is also proved that SCIL has continuously many semisimple subvarieties, and that the involutive algebras in SCIL are subdirect products of chains.

Completion and finite embeddability property for residuated ordered algebras.

A residuated ordered algebra is a partially ordered set with additional ‘residuated’ operations. A construction is presented that, from any partial subalgebra of a residuated ordered algebra, constructs a complete algebra into which the partial subalgebra embeds. Conditions are given under which the constructed algebra is finite whenever a finite partial subalgebra is chosen. This implies the ‘finite embeddability property’ for the given class of residuated ordered algebras. In the case that the whole algebra is chosen as the partial subalgebra, the construction is a completion of the underlying order of the algebra. A scheme of inequalities is described that are shown to have the property of being preserved by the above construction. These preservation results thus extend the results on the finite embeddability property and completion.