• Define _lean_init_ methods for some elements, parents, axioms, and categories #1019
• Prepare sagecell for working with passagemath #1058

References:

• [Merged by Bors] - feat: polyrith tactic leanprover-community/mathlib4#942 (2022)
• https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/Basic.20unverified.20symbolic.20calculations.20in.20Lean4.20using.20PARI/near/347676108 (2023)
• https://github.com/kim-em/lean-sage (2023)
• Discussion re Lean-Sage GSoC proposal https://leanprover.zulipchat.com/#narrow/channel/113488-general/topic/What.20should.20Sage.20look.20like.20in.20Lean.3F/with/523994993 (2024)
• feat: allow polyrith to use a local Singular/Sage install leanprover-community/mathlib4#20334 (2024)
• Calling Lean from Python via reverse FFI: https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/.E2.9C.94.20Calling.20Lean4.20code.20from.20Python/near/451861970
• https://github.com/riyazahuja/lean-m2, https://leanprover.zulipchat.com/#narrow/channel/113488-general/topic/LeanM2/with/523993718 (2025)
• https://leanprover.zulipchat.com/#narrow/channel/113488-general/topic/SOTA.20on.20symbolic.20algebraic.20systems.20written.20in.20Lean4/with/497553518 (2025)
• polyrith is broken because https://sagecell.sagemath.org/service is down and not coming back - https://leanprover.zulipchat.com/#narrow/channel/287929-mathlib4/topic/Polyrith.20error.20520/with/524076529 (2025)
• https://leanprover.zulipchat.com/#narrow/channel/113488-general/topic/Pitch.20for.20Webassembly.20support.20.28and.20follow-up.20projects.29/with/524928134 (2025)
• passagemath announcement: https://leanprover.zulipchat.com/#narrow/channel/113486-announce/topic/passagemath.2010.2E5.2E42.20.E2.80.93.C2.A0the.20pip-installable.20Sage.2C.20modularized/with/524344289 (2025)

Other Lean projects:

• https://github.com/lecopivo/SciLean/
• https://github.com/justincasher/lean-explore (python)

Continuation of:

• Meta-ticket: Connections to the Lean theorem prover sagemath/sage#34180