Computational and mathematical logic.

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Is `sort` typeable on elementary afine logic?

The following λ-term, here in normal form: ...
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38 views

Problem with the Inductive Types and recursors in LEAN

Reading the Lean online tutorial up to the section 6 "Inductive Types", I found a very confusing passage concerning the definition of the projection functions for the product type. Here is the ...
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1answer
129 views

What's wrong with this LEAN proof? [on hold]

I'm learning to use the LEAN theorem prover and I got stuck in a proof of a simple fact in first-order logic: $$ p(x) \rightarrow \forall x p(x) $$ My code is the following: variables (A : Type) ...
7
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1answer
193 views

An example where smallest normal lambda term is not fastest

Let the $size$ of $\lambda$-terms be defined as follows: $size(x) = 1$, $size(λx.t) = size(t) + 1$, $size(t s) = size(t) + size(s) + 1$. Let the complexity of a $\lambda$-term $t$ be defined as ...
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1answer
75 views

Concatenative binary lambda calculus/combinatory logic

John Tromp defines a version of the lambda calculus that is encoded in binary: https://tromp.github.io/cl/cl.html a) Does there exist a concatenative version of this language (or its combinatory ...
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41 views

applications of institution-independent model theory

To quote wikipedia, The notion of institution has been created by Joseph Goguen and Rod Burstall in the late 1970s in order to deal with the "population explosion among the logical systems used in ...
2
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1answer
138 views

Would a proof that the traveling salesman algorithm can't be encoded on LAL also prove P!=NP?

An answer to the traveling salesman (and similar) problems can be easily verified on light lambda-calculi. Also, if I understand correctly, the light lambda-calculi can compute every polinomial-time ...
4
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1answer
110 views

Example of $MSO_2$ definable NP-hard problem on bounded clique-width graphs

All $MSO_1$ and $MSO_2$ definable graph problems can be solved in linear time on bounded tree-width graphs by Courcelle's theorem. But it seems this theorem doesn't work for $MSO_2$ definable graph ...
13
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2answers
361 views

Smallest possible universal combinator

I am looking for the smallest possible universal combinator, measured by the number of abstractions and applications required to specify such a combinator in the lambda calculus. Examples of universal ...
7
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1answer
123 views

Formalized priority argument

A priority argument, an important proof technique in recursion theory, was introduced by Friedberg and Muchnik, to solve Post's Problem, i.e., the existence of two r.e. sets that do not Turing reduce ...
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1answer
83 views

Reference for CTL* logic

I need a reference for CTL* logic (preferably easy to understand). I have gathered some disperse information regarding temporal and CTL logic but I need a more orderly coverage. A chapter of the ...
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191 views

Courcelle's theorem for bounded clique-width graphs

Courcelle's theorem states that "Every graph property which is expressible in monadic second order logic is decidable in linear time for bounded tree-width graphs". Later it was extended to bounded ...
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86 views

What is the Kolmogorov complexity of arithmetic?

Chaitin's incompleteness theorem says no sufficiently strong theory of arithmetic can prove $K(n) > L$ where $K(n)$ is the Kolmogorov complexity of the number $n$ and $L$ is a sufficiently large ...
4
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1answer
113 views

Calculating least fixed points in equations

Given a set of relations/equations in some logic like LTL would it be possible to find a least fixed point for those equations? For example take the equations in LTL $$ P = Play ~\land X(P \cup S)\\ ...
11
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3answers
422 views

Why do constructivists not seem to care too much about call/cc

So a little while back I first had someone tell me that call/cc could allow proof objects for classical proofs by implementing Peirce's law. I did some thinking about the topic recently and I can't ...
2
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1answer
138 views

Deciding satisfiability and non-validity

For propositional logic, a decision procedure for satisfiability can be turned into a decision procedure for non-validity by giving it the negated version of a formula. Does this hold for all logics ...
7
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3answers
240 views

Ramification of An Impredicative Type Theory

Most type theories that I'm aware of are predicative by which I mean that Void : Prop Void = (x : Prop) -> x isn't well-typed in most theorem provers as this ...
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1answer
36 views

Is there a rule-based implementation of weighted abduction other than the PTTP?

Is there an implementation of weighted abduction other than the PT theorem prover? A Google search reveals the PTTP and a few statistical approaches but I'm interested in a rule-based approach. The ...
3
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3answers
221 views

Distinguishing semantics vs syntactic techniques and the syntax of your semantic domains

Consider a denotational semantics from simply-typed $\lambda$-calculus into dependent type theory. Is that actually a (trivial) term transformation into that dependent type theory? After all, type ...
9
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1answer
773 views

Why was there a need for Martin-Löf to create intuitionistic type theory?

I've been reading up on Intuitionistic Type Theory (ITT) and it does make sense. But what I'm struggling to understand is "why" was it created in the first place? Intuitionistic Logic (IL) and ...
5
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124 views

Comparing the Kolmogorov complexity of theories - Part 2

Chaitin's incompleteness theorem says no sufficiently strong theory of arithmetic can prove $K(x) > L$ where $K(x)$ is the Kolmogorov complexity of natural number $x$ and $L$ is a sufficiently ...
5
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1answer
298 views

Squash type vs Propositional truncation type

Homotopy type theory has a notion of propositional truncation type. It seems to me that it's strongly related to a notion of squash types. (See https://www.cs.kent.ac.uk/people/staff/sjt/TTFP/ttfp.pdf ...
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1answer
348 views

Logical framework vs type theory

What is the difference between logical framework and type theory? Both of them have types, terms, and are based on dependently typed lambda calculus. We have Edinburg LF which is based on lambda-pi ...
12
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1answer
315 views

Why was Schönfinkel's work on eliminating “bound variables” in logic so crucial?

AFAIK, The first evidence of using higher order functions goes back to Schönfinkel's 1924 paper: "On the Building Blocks of Mathematical Logic" - where he allowed one to pass functions as ...
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2answers
2k views

What was the original intent for the creation of Lambda calculus?

I've read that initially Church proposed the $\lambda$-calculus as part of his Postulates of Logic paper (which is a dense read). But Kleene proved his "system" inconsistent after which, Church ...
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2answers
178 views

Do past time LTL and future time LTL have the same expressiveness?

I would like to ask if anybody is aware of a paper comparing the expressiveness of past time LTL and that of (future time) LTL.
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1answer
56 views

Temporal Logic - Until [closed]

I have a doubt, in Linear Temporal Logic LTL, does the Until operator require that the first occurrence is the first term of the formula? ex: a U b does require ...
12
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1answer
361 views

Comparing the Kolmogorov complexity of theories

Chaitin's incompleteness theorem says no sufficiently strong theory of arithmetic can prove $K(s) > L$ where $K(s)$ is the Kolmogorov complexity of string $s$ and $L$ is a sufficiently large ...
10
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1answer
250 views

Practical applications of parity games

Are there examples of practical applications of parity games, ie systems, in the real world, that can be represented as parity games ? Usually related documentation on parity games has almost never a ...
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2answers
234 views

What is the complexity of the equivalence problem for read-once decision trees?

A read-once decision tree is defined as follows: $True$ and $False$ are read-once decision trees. If $A$ and $B$ are read-once decision trees and $x$ is a variable not occurring in $A$ and $B$, ...
10
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1answer
188 views

Reference for the fact that (0=1) implies false requires a universe in MLTT

It's a fairly well-known fact that deriving a contradiction from a disequality (for example, $(0=1) \to \bot$) in Martin-Loef type theory requires a universe. The proof is also fairly ...
5
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2answers
202 views

Law of excluded middle in MLTT

Is it possible to add law of excluded middle to Martin Lof Type Theory as an axiom? It seems to me, that it's possible to add it to Coq since Coq has a module for non constructive reasoning. Also, it ...
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462 views

Uses of $\infty$-categories in TCS

I'm not a theoretical computer scientist. I'm a stable homotopy theorist using $\infty$-categories. I've seen applications of category theory and topos theory to theoretical computer science, and I ...
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159 views

Are there any logics to formalize understanding?

Are there any logics (modal-based or others) to formalize the following statement: "agent A understands p". For example "agent A understands that Titanic sank because it hit an iceberg" Where ...
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46 views

Can we verify satisfiability of first order statements via saturation in sub-exponential time?

In first order logic, we can prove satisfiability several ways: Finite model generation, truthful monadic abstractions, and also saturation. With finite model generation techniques, we can verify the ...
5
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1answer
105 views

Logics for timed resource control

I'm studying proof theory and I've seen that linear logic can be used as a way to control resource usage, since by the propositions-as-types it is equivalent to the linear lambda calculus. Is there a ...
2
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2answers
119 views

Recommendations for References on undecidability of First Order Logic

I am currently reading Computability and Logic by Boolos Burgess Geoffrey for the proof on "undecidability of first order logic". however, I find the notations a bit confusing. Can anyone recommend ...
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162 views

Logic with Linear Programming

Can first-order logic be modeled/simulated as linear programming or integer programming? What about other forms of logic (say second order)? Update: am actually not a theory person, but more on the ...
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85 views

Presburger Arithmetic Decision Procedures

What are good textbook references for Presburger Arithmetic decision procedures?
8
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1answer
178 views

Simply typed lambda calculus and higher order logic

What is the relation between simply typed lambda calculus and higher order logic? Under Curry-Howard it seems that simply typed lambda calculus corresponds to propositional logic. How is it related ...
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43 views

what is the meaning of “indicate substitution by priming metavariables”

This is a question about the usage of "indicate substitution by priming metavariables". For example, in the separation logic(it is not important whether familiar to this logic), I can understand the ...
13
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2answers
483 views

Fixed points in computability and logic

This question has also been posted on Math.SE, http://math.stackexchange.com/questions/1002540/fixed-points-in-computability-nd-logic I hope it is ok to also post it here. If not, or if it is too ...
4
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1answer
149 views

What is a term of the type $\bot\rightarrow A$?

The sentence $\bot\rightarrow A$ is provable in intuitionistic logic for any type $A$. The proof is trivial: \begin{align} \bot&\vdash\bot \\ \hline \bot&\vdash A \\ \hline ...
13
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1answer
358 views

Scott's stochastic lambda calculi

Recently, Dana Scott proposed stochastic lambda calculus, an attempt to introduce probabilistic elements into (untyped) lambda calculus based on a semantics called graph model. You can find his ...
9
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1answer
129 views

First order satisfiability that doesn't have finite models

We know from Church's theorem that determining first order satisfiability is undecidable in general, but there are several techniques we can use to determine first order satisfiability. The most ...
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5answers
1k views

Are there any annotated formal verification systems for pure functional programming languages?

ACSL (Ansi C Specification Language), is a specification for C code, annotated with special comments, that allows C code to be formally verified. I have not looked into it, but I imagine that the ...
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1answer
87 views

Consistency and completeness of any arbitrary 3-valued logic? [closed]

Based on the explanations here [1] I know that 3-valued first order logic has many different versions, which differ in the definition of their operations (e.g. implication). All of these (as far as I ...
2
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1answer
170 views

Three-valued logic solver?

This is not my area, so apologizes if I am asking nonsense! I know that there are very good solver/theorem provers for solving 1st order logic. Now I have a problem, using 3-valued logic, but I am ...
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1answer
100 views

Decidability of first-order theory of real closed fields with functions

By a famous theorem of Tarski, the first-order theory of real closed fields is decidable, as it admits quantifier elimination. Can this result be extended so that propositions can be quantified over ...
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284 views

Theorem prover fails to find simple set theory proof?

I am trying to use an automated theorem prover (SNARK) to prove a theorem in first-order logic. Tarski claims in his "a work on mereology" that the goal is provable from assertions 1-3 but he does ...