Tags
A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.
The Rocq Prover used to be known as Coq. You should use the `rocq-prover` tag instead.
424 questions
Lean 4 is the latest major version of the Lean theorem prover by Microsoft Research. Use this tag for questions specific to Lean 4; if it's about Lean in general, use the tag (lean).
270 questions
Lean is a theorem prover and programming language, based on the calculus of constructions with inductive types. For version-specific questions, also add the [lean3] or [lean4] tags.
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Questions asked by a beginner user of proof assistants. We make an effort to be extra kind to such users.
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for questions about type theories, which are formal systems to specify properties of objects.
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For questions regarding Agda: the programming language / proof assistant.
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for questions about dependent types, which are families of types which vary over elements of another type.
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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 wi…
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A tactic is a command or instruction for constructing a formal proof by applying a common proof technique. For questions about high-level techniques for constructing proofs, use the tag (strategy).
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Mathlib is Lean's Math Library. The library is hosted on the GitHub
leanprover-community account. Do not use this tag for Lean the software. Do not use this tag for other math libraries of other pro…
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In terms of categorical semantics, an inductive type is a type whose interpretation is given by an initial algebra of an endofunctor. (from nLab)
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A proof assistant, or interactive theorem prover, is a software tool to assist with the development of formal proofs by human-machine collaboration.
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The Rocq Prover is a proof assistant, that was previously known as Coq. This tag should be preferred to `coq`.
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if you are implementing a proof engine, proof assistant or something similar in code. Do not use this tag if you are just at the design stage or asking about design decisions of existing …
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Questions pertaining to equality in type theory (all kinds of equality are included: judgemental, propositional, observational, setoid equality, etc.) and equality reasoning in proof assistants.
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Lean 3 is the previous version of the Lean theorem prover, and has an active "community" release. If using the final "official" release from 2019 (3.4.2) which is incompatible with [mathlib], make thi…
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Tag for questions about induction such as mathematical induction, structural induction or well-founded induction (Noetherian).
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used for questions that ask for software with a certain property or goal, such as automated theorem provers for equational logic. If the question is not specifically for software consider …
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Categories are structures containing objects and arrows between them. Many mathematical structures can be viewed as objects of a category, with structure preserving morphisms as arrows. Reformulating …
28 questions
In mathematics, and particularly in set theory, category theory, type theory, and the foundations of mathematics, a universe is a collection that contains all the entities one wishes to consider in a …
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Questions requesting papers or books in the literature on specific, narrow issues. Also consider the tag [recommendations].
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Cubical type theory is a version of homotopy type theory in which univalence is not just an axiom but a theorem, hence, since this is constructive, has “computational content”. Cubical type theory mod…
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for questions about mathematical or logical foundations of proof assistants. Questions should be related in some way to proof assistants. Possible topics might include mathematical modell…
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Questions asking how to properly and efficiently use Proof Assistants.
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for questions a mathematician would feel at home answering and can be traced back to an area of mathematics.
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For questions regarding ATP's (Automatic Theorem Provers), which attempt to prove a theorem without any assistance. If you are using a Proof Assistant or an interactive theorem prover and are providin…
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Homotopy type theory is a flavor of type theory – specifically of intensional (Martin-Löf-) dependent type theory – which takes seriously the natural interpretation of identity types as formalizing pa…
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For use with the proof assistant Isabelle with classical higher-order logic.
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when a question is related to specifics on how a proof assistant works. Do not use this tag for questions related to using a proof assistant.
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Set theory is the branch of mathematics that studies unordered collections of objects. Questions with this tag will involve proofs about sets or operations on them.
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when asking a question that is not about a specific Lambda-calculus such as pure, typed, etc.
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For question about natural numbers $\Bbb N$, their properties and applications
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The Cubical mode extends Agda with a variety of features from the CHM version of Cubical Type Theory. In particular, computational univalence and higher inductive types which hence gives computational…
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