leanprover-community/mathlib4

The math library of Lean 4

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4 beginner-friendly issues open

Improve `Multipliable.inv` / `inv₀` docstrings for `ℂ` (and add `tprod_one_add_ne_zero_of_summable` cross-reference Open

Difficulty 2/5 1-3 hours Newbie friendliness 74/100

leanprover-community/mathlib4#43872 · Opened Sep 16, 2026
Notation for multilinear maps Open

good first issue

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

leanprover-community/mathlib4#43855 · Opened Sep 16, 2026
Nonexistent `SetRel.map` in example Open

Difficulty 2/5 1-3 hours Newbie friendliness 65/100

leanprover-community/mathlib4#39396 · Opened May 14, 2026
Delaborator for "not an element" doesn't check for mdata Open

Difficulty 2/5 1-3 hours Newbie friendliness 62/100

leanprover-community/mathlib4#8575 · 2 comments · Opened Nov 22, 2023

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