catgraph

Category-theoretic graph structures in Rust, anchored to the source papers: a strict implementation of Fong & Spivak, Hypergraph Categories (2019), with applied-CT, magnitude, Wolfram-physics, and categorical-deep-learning extensions.

Status: the five proven crates (core / applied / magnitude / physics / dl) have landed. The algebraic substrate is entirely catgraph's own (#218, completed at #222) — the Rig semiring and its Zero / One identities live in catgraph-applied, the endofunctor / Free / Cofree substrate in catgraph-dl, and the value-level Arrow algebra in catgraph-syntax. No deep_causality_* crate is a dependency anywhere (CI-guarded); the API shape of the latter two originated as a port from deep_causality_haft 0.4.2, whose MIT notice is therefore retained in THIRD-PARTY.md and the defining files. Zero external algebraic dependencies, with nalgebra kept optional and numeric-only. Versioning is workspace-wide (tags v0.1.0 → v0.15.0) and work is tracked as GitHub issues. Phase 6 (catgraph-syntax, the Arrow presentation frontend, #5): the S1–S5 milestone surface is complete (printer, parser + presentation files, interpreter, Frobenius layer, Traced typed builder), and the post-milestone follow-ups have all shipped — #80 (Cospan-valued complete functor) and #81 (serde) at v0.4.0, #79 (Λ-colored props) completed at v0.5.0.

Workspace

Crate	Paper anchor
catgraph	Fong & Spivak 2019 — Hypergraph Categories; secondary: F&S 2018 (Thm 6.55 spider tests, Ex 6.64 Corel)
catgraph-applied	Fong & Spivak 2018 — Seven Sketches in Compositionality
catgraph-magnitude	Bradley–Vigneaux 2025; Leinster 2008/2013/2017
catgraph-physics	Wolfram-physics extensions (DPO rewriting, multiway, branchial)
catgraph-dl	Gavranović et al., ICML 2024 — Categorical Deep Learning
catgraph-syntax	F&S 2018 Ch. 5 (props/presentations) + F&S 2019 (Frobenius layer); term language over catgraph-applied's NF engine
catgraph-testutil (dev-only, unpublished; [dev-dependencies] only, #33)	—

Build

cargo build  --workspace
cargo test   --workspace
cargo clippy --workspace --all-targets -- -D warnings          # the CI gate (default lints)
cargo clippy --workspace --all-targets -- -W clippy::pedantic  # advisory local pass (non-gating)

License

MIT — see LICENSE.