leanprover/cslib

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The Lean Computer Science Library (CSLib)

Stars: 709
Forks: 200
Open beginner issues: 0
Indexed issues: 49
Avg merge: 3d 6h
Merged PRs (30d): 45

Dominant language: Lean
License: Apache-2.0
Last GitHub push: Sep 20, 2026
Latest indexed: Sep 20, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted

Beginner friendly Everything

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49 open issues indexed

upstream this generalisation of Mathlib's `smulCommClass_self`, which applies only to Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

leanprover/cslib#824 · Opened Aug 20, 2026
upstream this generalisation of Mathlib's `smulCommClass_self`, which applies only to Open

Difficulty 3/5 1-2 days Newbie friendliness 64/100

leanprover/cslib#823 · Opened Aug 20, 2026
adapt `topNamespace` to the module system Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

leanprover/cslib#790 · Opened Aug 10, 2026
`listFullBeta_cons_r` should rename to `listFullBeta_concat_r` Open

Difficulty 1/5 Under an hour Newbie friendliness 72/100

leanprover/cslib#784 · Opened Aug 9, 2026
Add tests for capture-avoiding substitution in lamba calculi Open

help wanted

Difficulty 4/5 3-5 days Newbie friendliness 55/100

leanprover/cslib#711 · 2 comments · Opened Jul 12, 2026
feat(Computability): quantum computing foundations Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

leanprover/cslib#688 · Opened Jul 1, 2026
Proposal: lawful lenses for verified state access Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

leanprover/cslib#658 · Opened Jun 17, 2026
IsIntuitionistic should be generalised outside the `PL` scope, once we have typeclasses to express that a type possesses an implication connective. Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

leanprover/cslib#655 · Opened Jun 16, 2026
this should be Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

leanprover/cslib#654 · Opened Jun 16, 2026
this should Open

Difficulty 3/5 1-2 days Newbie friendliness 25/100

leanprover/cslib#653 · Opened Jun 16, 2026
this should Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

leanprover/cslib#652 · Opened Jun 16, 2026
Logics and WP calculi: First-order logic, Second-order logic, Henkin semantics, Separation Logic Open

Difficulty 5/5 Over a week Newbie friendliness 20/100

leanprover/cslib#646 · 2 reactions · Opened Jun 14, 2026
develop an attribute to dualize theorems to the converse of a relation Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

leanprover/cslib#644 · Opened Jun 13, 2026
TimeM's `✓` tick breaks when HasWellFormed is imported Open

Difficulty 5/5 Over a week Newbie friendliness 45/100

leanprover/cslib#638 · Opened Jun 12, 2026
feat(Computability): Plan for complexity theory Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

leanprover/cslib#611 · 2 comments · Opened Jun 1, 2026
Loogle for Cslib Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

leanprover/cslib#594 · 1 comment · Opened May 23, 2026
feat(Computability): Framework for encoding arbitrary types on Turing machines Open

Difficulty 5/5 Over a week Newbie friendliness 48/100

leanprover/cslib#590 · Opened May 21, 2026
upstream to Mathlib as a FinEnum instance for BitVec. Open

Difficulty 3/5 1-2 days Newbie friendliness 55/100

leanprover/cslib#494 · Opened Apr 15, 2026
upstream to Mathlib — general BitVec XOR cancellation lemma. Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

leanprover/cslib#493 · Opened Apr 15, 2026
feat: Mergesort Stability Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover/cslib#438 · 1 comment · Opened Mar 18, 2026
feat(CellularAutomata): One-Dimensional Cellular Automata for Language Recognition Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

leanprover/cslib#407 · Opened Mar 8, 2026
timing of bump_toolchain_nightly-testing.yml Open

Difficulty 4/5 3-5 days Newbie friendliness 30/100

leanprover/cslib#394 · Opened Mar 3, 2026
Define the weak exponential of two LTSs Open

Difficulty 5/5 Over a week Newbie friendliness 30/100

leanprover/cslib#390 · Opened Mar 2, 2026
Define the product of two LTSs Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

leanprover/cslib#388 · 3 comments · Opened Mar 2, 2026
remove `h_mono` assumption Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover/cslib#378 · Opened Feb 27, 2026
notation for multiple substitution Open

leanprover/cslib#374 · 3 comments · 1 assignee · Opened Feb 26, 2026
Local EF games: extracting partial isomorphisms from bounded Duplicator wins Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

leanprover/cslib#359 · Opened Feb 20, 2026
Custom setoid on lists cannot use the `\~~` notation. Open

Difficulty 3/5 1-2 days Newbie friendliness 25/100

leanprover/cslib#352 · Opened Feb 18, 2026
fix proof to work with backward.isDefEq.respectTransparency Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

leanprover/cslib#351 · Opened Feb 18, 2026
fix proof to work with backward.isDefEq.respectTransparency Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

leanprover/cslib#350 · Opened Feb 18, 2026
fix proof to work with backward.isDefEq.respectTransparency Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

leanprover/cslib#349 · Opened Feb 18, 2026
fix proof to work with backward.isDefEq.respectTransparency Open

Difficulty 3/5 1-2 days Newbie friendliness 35/100

leanprover/cslib#348 · Opened Feb 18, 2026
fix proof to work with backward.isDefEq.respectTransparency Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

leanprover/cslib#347 · Opened Feb 18, 2026
fix proof to work with backward.isDefEq.respectTransparency Open

Difficulty 3/5 1-2 days Newbie friendliness 38/100

leanprover/cslib#346 · Opened Feb 18, 2026
grind sets Open

Difficulty 5/5 Over a week Newbie friendliness 28/100

leanprover/cslib#308 · 8 comments · 1 reaction · Opened Jan 31, 2026
Automate `lake update` PRs Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover/cslib#294 · Opened Jan 26, 2026
move meta sections into new files Open

leanprover/cslib#264 · 1 assignee · Opened Jan 12, 2026
`grind` does not use congruence relations with `na.totalize.MTr` Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

leanprover/cslib#253 · Opened Jan 9, 2026
Grind rules for `Automata.NA.addHist` Open

Difficulty 5/5 Over a week Newbie friendliness 35/100

leanprover/cslib#191 · 1 comment · Opened Nov 29, 2025
Grind rules for Computability.Automata.NA.Run Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

leanprover/cslib#174 · Opened Nov 20, 2025
Performance Profiling Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

leanprover/cslib#136 · 2 comments · Opened Oct 29, 2025
precedence for `ReductionSystem` and `LTS` notations Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

leanprover/cslib#109 · Opened Oct 15, 2025
MSequent.allQuest should return a Boolean. Open

logic

Difficulty 1/5 Under an hour Newbie friendliness 72/100

leanprover/cslib#74 · Opened Sep 24, 2025
Sequent.allQuest should return a Boolean. Open

logic

Difficulty 2/5 1-3 hours Newbie friendliness 45/100

leanprover/cslib#72 · Opened Sep 24, 2025
Proof-relevant logical equivalences. Open

logic

Difficulty 3/5 1-2 days Newbie friendliness 38/100

leanprover/cslib#71 · Opened Sep 24, 2025
Proof-relevant substitution principles for logical equivalence in CLL. Open

logic

Difficulty 2/5 1-3 hours Newbie friendliness 55/100

leanprover/cslib#70 · Opened Sep 24, 2025
Proof-relevant substitution principles for logical equivalence in CLL. Open

logic

Difficulty 3/5 1-2 days Newbie friendliness 45/100

leanprover/cslib#69 · Opened Sep 24, 2025
`create_{lts,reduction_sys}` do not generate equational theorems Open

leanprover/cslib#55 · 1 assignee · Opened Sep 3, 2025
Notation and term elaborators Open

leanprover/cslib#23 · 3 comments · 2 assignees · Opened Jul 28, 2025

leanprover/cslib

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