Questions tagged [lo.logic]

Computational and mathematical logic.

Filter by
Sorted by
Tagged with
14
votes
0answers
149 views

Counting solutions to extended MSO formulas, and sampling — do these appear in the literature?

I am trying to determine if the literature contains various extensions of Courcelle's theorem. Since I haven't been able to find these in the literature, I guess that these are folklore results, or ...
2
votes
0answers
78 views

Forward chaining algorithms

I am interested in learning about the current state of the art regarding forward chaining production systems. I understand that things haven't changed much (regarding the basic algorithms) since 1995'...
7
votes
0answers
202 views

Reverse Skolemization?

I'm wondering if there are any references on "reverse skolemization", that is, converting a formula with functions into one purely consisting of quantifiers by eliminating function applications. I'm ...
0
votes
1answer
85 views

How to build comparison operator (comparator) in an arithmetic circuit

I am trying to convert a basic program into an arithmetic circuit. I am stuck on the step of converting the greater than operator into an arithmetic circuit. To be specific, I do not know how to ...
0
votes
0answers
69 views

What is sequence unification?

And why is it interesting? Please provide some examples. This text is here to circumvent the anti-spam filter which thinks my question is bad.
4
votes
2answers
201 views

How do continuations represent negations (under the Curry–Howard correspondence)?

Under the Curry–Howard correspondence, types can be thought of as propositions, and values inhabiting a type can be thought of as proofs that the corresponding proposition is true. (E.g., the ...
3
votes
0answers
43 views

Extending the sequential calculus (logic over words) to allow a hierarchy of languages like the arithmetical hierarchy

Let $\Sigma$ be some finite alphabet. Then consider the logical language $\mathcal L = \{ R_a : a \in \Sigma \} \cup \{ <,= \}$ and first order formulas. For a given first order formula $\varphi$ a ...
3
votes
1answer
127 views

Reductions in Descriptive Complexity

Reducing one problem to another are well known in various settings, such as many-one, randomized, truth-table, logspace or a whole slew of other reductions. Descriptive complexity can alternately ...
2
votes
0answers
94 views

Notion of “quotient” or “inverse” for recognizable tree languages?

Related to my previous question but this time I have a better idea of what I'm actually asking. I'm looking at the following operation on recognizable tree languages (i.e. regular tree grammars, ...
6
votes
2answers
616 views

What logic correponds via Curry-Howard to a Monad?

According to Moggi's 1991 paper "Notions of computation and monads" one can represent monadic equational logic with the well known monad $(T, \eta, \mu)$ with T an functor and the two natural ...
3
votes
2answers
151 views

Compactness of domino tilings

I've read in Lemma 2 of the paper 1 that if every square region of the plane admits a tiling, then the whole plain admits a tiling, but the proof is omitted. This sounds like a compactness property, ...
1
vote
1answer
112 views

Dependent C-style types with subtyping rule

I'm looking for previous work regarding an extension of a C-style type system in which types may have constraints and have a defined subtyping rule. In particular, I'm interested in defining algebra-...
9
votes
1answer
252 views

What is the reference for the proof Gödel's first incompleteness theorem based on the undecidability of the halting problem?

A weaker form of Gödel's First Incompleteness Theorem, direct proofs of which in Gödel's manner are lengthy, involved and at some place rather counter-intuitive, has a simple and intuitive proof based ...
9
votes
1answer
174 views

P and Descriptive Complexity

In the Complexity Zoo, it says [1] that, in descriptive complexity, $P$ can be defined by three different kind of formulae, $FO(LFP)$ which is also $FO(n^{O(1)})$, and also as $SO(HORN)$. However, ...
6
votes
2answers
231 views

Is case analysis on normal forms of lambda terms sufficient to prove parametricity results?

There are many closed terms of a given type. For instance, both of these terms: $$ \lambda x . x $$ $$ \lambda x . (\lambda y . y) x $$ have a type of a polymorphic identity function: $$ \forall X ....
7
votes
3answers
307 views

When a type is a value?

In functional programming and in the theoretical setting of the $\lambda$-calculus it is standard to consider a lambda abstraction $\lambda x.M$ as a value. In my understanding, the intuitive reason ...
3
votes
0answers
131 views

Busy Beaver Equivalent for the Untyped Lambda Calculus

In the same way that the Busy Beaver function is defined for Turing Machines, we could define a similar function for the untyped lambda calculus: Over all terms in the ULC composed of ...
10
votes
2answers
313 views

Hereditary substitution with a universe hierarchy

I've read about hereditary substitution for the Simple Lambda Calculus and for The Logical Framework with distinct terms and types. I'm wondering, are there any examples of hereditary substitution in ...
9
votes
0answers
97 views

Results in denotational semantics from model theory?

Denotational semantics interpret the theories of various lambda calculi in various (set-theoretic, domain-theoretic, category-theoretic, game...) models. Let $T$ be the theory of one such lambda ...
9
votes
1answer
184 views

Understanding the Proof of Strong Normalization of the Calculus of Constructions

I have difficulties in understanding the proof of strong normalization for the calculus of constructions. I try to follow the proof in the paper of Herman Geuvers "A short and flexible proof of Strong ...
1
vote
1answer
64 views

Soft Truth Values in the PSL model

This might sound like a trivial question. But since am starting out with my research in an area that is entirely new to me, I would really appreciate it if someone could kindly elucidate what Soft ...
10
votes
0answers
128 views

Do Banach spaces and linear contraction maps form a model of ILL with an exponential?

Recently, I read on the nLab that the category of Banach spaces and linear contractions is small complete, small cocomplete, and monoidal closed. This means that Banach spaces and short linear maps ...
4
votes
2answers
173 views

What does the category of RDF models look like in Institution Theory?

The Question in short Here is the question in its pure form. Details of my reasoning can be found below. The RDF1.1 spec semantics defines a model to consist of a set IR of objects and IP of ...
6
votes
3answers
209 views

Why/when do we ever need transfinite loop variants?

I do not understand why one would ever need a transfinite loop variant. Why do natural-number-valued variants not suffice? My simple (but perhaps too naive) argument is: if a loop $L$ terminates ...
8
votes
0answers
43 views

Relationship between lambda-definability, specification and definability in model theory

I am new to lambda calculus and definability theory, and I am trying to clarify my understanding of the relationship among the following concepts: An element $a$ in the domain of a type $A_\sigma$ is ...
3
votes
1answer
71 views

Multimodal logic with quantification over modal operators

I take a multimodal logic to be a logic with multiple (potentially infinitely many) primitive modal operators. I am curious if anyone has studied a logic that allows one to quantify over the modal ...
11
votes
5answers
386 views

Representing bound variables with a function from uses to binders

The problem of representing bound variables in syntax, and in particular that of capture-avoiding substitution, is well-known and has a number of solutions: named variables with alpha-equivalence, de ...
4
votes
1answer
143 views

Is graph connectivity definable in existential MSO with vertices and edges?

Can $\exists$MSO$_2$ express graph connectivity? Monadic SO (MSO) is the fragment of second-order logic in which the second-order quantifiers range over relations of arity 1 only. $\exists$MSO is the ...
2
votes
1answer
87 views

Representable functions on System T

In Proof and Types by Girard et alii. Section 7.4.2, I think that the authors want to show that: (1) The set of functions definable in System T coincides with the set of recursive functions whose ...
1
vote
1answer
93 views

What's the expressive/compressive power of strongly normalizing subset of untyped lambda calculus?

Let $\Lambda$ be a set of strongly normalizing lambda terms. Let $\mathtt{NF} : \Lambda \rightarrow \Lambda$ be evaluation to the normal form. Let $ \lvert x\rvert : \Lambda \rightarrow \mathbb{N}$ be ...
7
votes
1answer
530 views

Is Church-pentation implementable in Agda?

Inspired by suggestion in this question, I've implemented predicative Church encoding of Peano arithmetic. Exponentiation works fine, unfortunately tetration requires the level of one of the arguments ...
5
votes
2answers
105 views

A stronger multiplexing rule for soft linear logic?

In (intuitionistic) linear logic the usual rules for the storage modality $!$ are promotion, dereliction, contraction, and weakening: $$\frac{!\Gamma\vdash A}{!\Gamma\vdash !A}(prom) \qquad \frac{\...
4
votes
1answer
108 views

What's the difference between proving weak normalization and implementing evaluator?

Implementing an normalization (cut elimination) procedure for a type system A in a language with a total type system B, automatically proves cut elimination for type system A since the implementation ...
1
vote
0answers
193 views

Is it possible to type Ackermann function with (stratified variant of) System F?

I was surprised to find no open-source implementation of Ackermann function in pure System F as an illustrative example. I finally managed to implement it myself in Haskell using Church encoding: <...
2
votes
1answer
101 views

Is there a formalization of normalization of impredicative system F?

In particular Agda seems not strong enough to prove that. Is the predicative Calculus of Inductive Constructions universes (Coq without Prop) sufficient? How about with the impredicative Prop?
1
vote
1answer
52 views

Is there a standard format for Dependent QBF?

I know there is a standard input format DIMACS for a formula is in conjunctive normal form (CNF) and QDIMACS for quantified Boolean formulas. Is there a similar standard format for the Dependent-QBF (...
7
votes
1answer
119 views

Does this variant of Multiplicative Linear Logic with mix rule enjoy cut elimination?

In Multiplicative Linear Logic (MLL), addition of the mix rule eliminates 'connectedness' from Danos-Regnier criterion. I'm investigating how the criterion changes if we do not distinguish between ...
3
votes
1answer
47 views

Algorithm for finding smallest set and instanciation for a given constraint system

I have a system of constraints described by a set of clauses of the form $x_1 \neq x_2 \lor \dots \lor x_{i-1} \neq x_i$, for instance: ...
1
vote
0answers
57 views

To what extent supervised learning ERM learn first-order knowledge

Suppose I have a collection of (hidden) first-order rules: $$ \mathcal{R}: \{ Q_i(x) => P_i(x) \}_{i=1}^{k} $$ all defined over $x \in \mathcal{X}$. I can use these rules and (automatically) ...
3
votes
0answers
112 views

Decomposition of rectangular relations

Let $\alpha$ be a binary relation from $\gamma$ to $\chi$ and $\beta$ a binary relation from $\chi$ to $\rho$. If both $\alpha$ and $\beta$ are rectangular, i.e., they satisfy $\alpha \alpha^{-1} \...
4
votes
0answers
141 views

Formalization of proofs and CC paradox? - Part II

This was the second part of my previous question. It is very similar, and probably it has a similar answer (as Emil said in a comment), but I thought it was worth to separate it and ask it as a new ...
7
votes
1answer
342 views

Formalization of proofs and computational complexity paradox?

While reading some articles on formal proofs (see also my previous question on cstheory about the length of ZFC proofs versus human written proofs), I came up with this apparent paradox. Let $M_{...
5
votes
0answers
175 views

Is Agda sound as a proof system? [closed]

I've asked the same question on CSSE but with no luck (https://cs.stackexchange.com/questions/89611/is-agda-sound-as-a-proof-system). Therefore I ask it again here in cstheory and hope that more ...
5
votes
1answer
454 views

Sparsification Lemma for k-SAT and Exponential Time Hypothesis

According to R. Impagliazzo, R. Paturi and F. Zane, 2001 an instance of $k$-SAT is called sparse if $m = O(n)$ where $m$ denotes the number of clauses and $n$ the number of variables. The ...
3
votes
0answers
88 views

Looking for a specific tree automata model

is there any tree automata model over unranked trees (that is with unbounded number of children for each node), such that: Checking non-emptiness and universality is decidable in elementary time, ...
2
votes
1answer
104 views

Is Eulerian Path (or Eulerian Cycle) definable in Monadic Second Order Logic?

Does there exist a monadic second order logic formula which is satisfied by a graph if and only if it has an Eulerian path (or Eulerian cycle). I am looking for properties of graphs which are ...
6
votes
0answers
219 views

Fischer and Rabin's theorem (1974) for theories of “additive” structures

Fischer and Rabin's Super-Exponential Complexity of Presburger Arithmetic (1974) has the following theorem. (Theorem 12) Let $U$ be any class of additive structures, so if $A = (A, +) \in U$, ...
2
votes
0answers
41 views

Is there a complete and finite axiom scheme for conditional independence? (Graphoids)

Note: This is a better-written version of an unanswered question asked before on MathOverflow. Question: Is there a complete and finite axiom scheme for conditional probability? If so, is ...
3
votes
1answer
114 views

Connection between algebraic logic and computational complexity of logics?

I'm learning a bit about algebraic logic and I was wondering how knowing the algebraic semantics of a given logic might help the study of the logic itself from a computational point of view. In ...
8
votes
1answer
386 views

Complexity of modal logic IK5

What is the complexity of local satisfiability problem for modal logic $\mathit{IK5}$? Herein we denote by $IK5$ the modal logic over euclidean frames extended with inverse modality. Could you provide ...