# Questions tagged [isabelle]

Use this tag with the proof assistant Isabelle, if your question is specific to a certain object logic please use the corresponding tag (eg. questions specific to Isabelle/HOL should also be tagged with (isabelle-hol)).

34 questions
Filter by
Sorted by
Tagged with
381 views

### Why is Isabelle usually not just Isabelle but Isabelle/<xyz>?

For most proof assistants the name alone is common, E.g. Coq, Lean but with Isabelle it is often seen as Isabelle/<xyz>? Why the two parts? What is Isabelle/HOL Isabelle/FOL Isabelle/ZF ...
• 2,836
278 views

### How can all functions be total in Isabelle?

Isabelle/HOL’s logic is called a logic of “total functions”, yet there are functions that are obviously not total, such as division div. How does this make sense?
• 1,844
193 views

### Code generation from Locales and Sublocales in Isabelle

Problem Description I stumbled on this limitation/misunderstanding several times when using locales and sublocales in Isabelle. As a minimal example, let us extend the locale from the example in ...
• 1,098
266 views

### What are "locales" in Isabelle?

How does it compare to dependent records in Agda/Lean/etc.? I heard that locales in Isabelle are used to model algebraic structures in a talk, bu. Isn't this a kind of dependent type in some sense? Is ...
• 5,974
222 views

### How "generic" are "generic proof assistants"?

I've read that Isabelle and Metamath (and maybe Andromeda) are "generic" proof assistants in some sense that allows them to be used to implement different theories such as HOL, ZF and ...
• 304
779 views

### Learning Math Proof via Proof Assistants

I want to learn proof based mathematics and it looks like a proof assistant like Coq and Lean could be a good way to go about verifying my proofs, without needing a PhD on hand to check through all my ...
201 views

### Generic proof assistants/modularity of the proof assistants?

One notable feature of Isabelle is that it allows for the definition and in-built integrated support of alternative object logics via the interface of Isabelle/Pure in combination with Isabelle/Isar. ...
53 views

### Are subclass and instance commands equivalent in defining subclass relation between typeclasses in Isabelle?

Given two typeclasses (e.g. group and monoid), I have seen both the subclass and the ...
• 1,906
192 views

### How to prove Gauss summation of integers with proof assistants using forward reasoning?

As shown in an exercise here, we can prove the Gauss summation (that $\Sigma_{i=0..n}{i} = n \cdot (n + 1)/2$ ) in Isabelle/Isar using mathematical induction, as follows. ...
• 1,906
92 views

### Is there a way to convert free variables to (meta) universally quantified variables in Isabelle?

Universally quantified variables are the same as free variables in the following two lemmas from the Isabelle (2021) tutorial section 8.1.2 (with slight changes on the second one): Given ...
• 1,906
141 views

### What are some useful resources for a mathematician interested in learning Isabelle/HOL?

What are some useful and reliable resources for a mathematician interested in learning Isabelle/HOL? Could be online (websites) or physical (books).
• 1,308
139 views

### How does a logical framework become a meta-logical framework?

In a recent answer, Isabelle was noted as a Logical Framework. A comment noted it was a Meta-Logical Framework. In researching for an understanding found "Logical and Meta-Logical Frameworks"...
• 2,836
245 views

### Tracing the classical reasoner in Isabelle

Some time ago I asked this question on Stack Overflow but got no answer: https://stackoverflow.com/questions/60521384/tracing-tactics-in-isabelle Section 9.4 The Classical Reasoner of the Isar ...
• 299
192 views

### Is there a way to use sledgehammer in Isar proofs?

I tried to use the sledgehammer command in Isabelle/HOL (2021) after the proof command, and got an error: Illegal application ...
• 1,906
310 views

### (Dis)Advantages of basing a proof assistant on CH correspondence?

Major proof assistants like Lean and Coq are fundamentally based on the Curry-Howard correspondence: propositions are encoded as types, quantified propositions are encoded as dependent types, proofs ...
• 293
181 views

### Standard ML is used for many proof systems. Is there a recommended implementation to use for Isabelle?

Is there a recommended implementation of Standard ML to use for Isabelle? Note: An answer should strive to include why that implementation (noted in build instructions is acceptable). While not needed ...
• 2,836
132 views

### Architecture of Isabelle: What parts are written in SML? What parts are written in Scala? What does the boundary look like?

My question is based on this question, which asks about swapping out different SML implementations when building Isabelle. I've read on Wikipedia that Isaballe is written in Scala and SML. Based on ...
• 2,711
72 views

### How to rename a type class operator in a subclass in Isabelle/HOL?

I am trying to define a hierarchy of type classes with binary operations, in which the base class defines a binary operation binop and then each class ...
• 1,906
90 views

### How can I derive other type classes in Isabelle/HOL?

The AFP entry Deriving provides a way to derive the following classes: class description comparator generate comparators for given types compare register types in class compare compare_order ...
• 1,098
79 views

### Semantics verification of an LTL fragment logic

I am a beginner to Isabelle and I went over the proof documentation. I am trying to implement a fragment logic of LTL over finite intervals and finite traces called MLTL, the syntax and semantics can ...
• 53
157 views

### New types in higher order logic

From my understanding, most descriptions of higher order logic have a clear "phase distinction": We first describe the types, which are usually syntactically simple trees. For concreteness, ...
• 3,718
33 views

### Implementing object-logics in Isabelle Best Practices?

I'm patching up Isabelle/Mizar to work with Isabelle2023, and I am wondering what are the best practices for implementing an object logic in Isabelle? (Usually there is great documentation for ...
• 1,529
67 views

### Particularization in algebraic statements in Isabelle

I'm new to Isabelle and I'm still becoming familiar with the basics. I have an algebra for which (x || y) ; (z || w) <= (y ; z) ; (x || w) is an axiom, ...
• 33
31 views

### Picking this and calculation in Isabelle/JEdit output

This is a follow-up to How to write a low-level proof in Isar? Having ...
• 299
159 views

### Existential quantification on types in Isabelle

We are currently working on a proof of compactness for classical first order logic using the ultraproduct-based proof. ...
• 133
53 views

### Why are modules also rings in the HOL-Algebra library?

We would like to use vectors and matrices (2x2 and 3x3) in a project, and have found the Jordan Normal Form AFP entry (Matrix.thy) which provides a concrete ...
• 131
28 views

### ROOT file for building a heap image in Isabelle

I use Isabelle, and I have a theory that is processed for long interactively so I wanted to build a heap image. Therefore I created a ROOT file: ...
• 299
111 views

### How do I do for-all introduction in Isabelle?

It's pretty easy to prove something like this: theory Scratch imports Main begin theorem "foldl (λ x y. x) a b = a" apply (induction b) by auto ...
• 495
74 views

### Disjoint unions in Isabelle/HOL

In mathematics there is a notion of a "disjoint union" in which you "consider" all of the sets to be disjoint even if they are not. For instance, you might want to take the ...
1 vote
121 views

### Is the Archive of Formal Proofs indexed in journal databases?

I was wondering if journals that publish regularly formal proofs are indexed in journal databases like Scopus or Web of Science. Apparently, this is not the case. Why is it so?
• 111
1 vote
22 views

### Referring to a session properly in another ROOT file in Isabelle

This is a follow-up to ROOT file for building a heap image in Isabelle . I have a main directory where my main theory resides. I have a ROOT file there: ...
• 299
1 vote
38 views

### Characterization of capability-based security in Isabelle/HOL

I am looking for a formal characterization of Capability-based security in Isabelle/HOL using a set of invariants that "is complete". I'm not exactly sure what "complete" means, ...
• 111