sparql-formal-semantics SKILL.md skillA
sparql-formal-semantics from sparq-org/sparq is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add sparq-org/sparq/sparql-formal-semantics@git:20260612.13b231cPins git:20260612.13b231c in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- sparq-org/sparq
- Path
.claude/skills/sparql-formal-semantics/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260612.13b231c, committed Jun 12, 2026
- Size
- 4,101 bytes
- Repository stars
- 13
- License
- MIT
Cheat-sheet for the formal semantics of the SPARQL fragment used in the ZKP-SPARQL paper — Pérez–Arenas–Gutiérrez algebra, RDF graph model, blank-node canonicalisation choices, fragment-scoping conventions. Use when writing operator specs, scoping which SPARQL constructs the paper supports, drafting semantics sections, or reconciling differences between the W3C SPARQL 1.1 rec and the paper's formalisation.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# SPARQL formal semantics cheat-sheet A working reference for the formal semantics layer Jesse's paper sits on. Citations matter — every claim here should be traceable to either the W3C SPARQL 1.1 rec or to the Pérez–Arenas–Gutiérrez (PAG) paper. ## Algebra at a glance PAG models a SPARQL graph pattern as expressions built from: - **Triple patterns** `(s, p, o)` where each position is a term or variable. - **Basic graph patterns (BGPs)** as sets of triple patterns. - **AndP1, P2** — join (compatibility on shared variables). - **OptP1, P2** — left outer join (`OPTIONAL`). - **UnionP1, P2** — set union of solution mappings. - **FilterP, R** — selection by a built-in expression. Solutions are partial functions `μ : V → Term` (called solution mappings). The semantics `eval(G, P)` of pattern `P` over graph `G` is a multiset of solution mappings. ## Compatibility Two solution mappings `μ1`, `μ2` are *compatible* iff they agree on every variable in `dom(μ1) ∩ dom(μ2)`. The join `μ1 ⨝ μ2` is defined when they're compatible and equals `μ1 ∪ μ2`. This single notion unifies BGP joining, `AND`, and the inner part of `OPTIONAL`. ## Standard equivalences …
Read the whole file at its exact version.
How to install
mdr add sparq-org/sparq/sparql-formal-semantics@sha256:7ceaaec34531353fThe line at the top of this page pins the label git:20260612.13b231c, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_fl7omqqshzodikva)
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Versions
The registry has recorded 1 version of this file, committed on Jun 12, 2026.
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Source
sparq-org/sparq · 13 stars · license MIT · pushed 2026-10-29 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_fl7omqqshzodikva GET https://markdownregistry.com/api/v1/resolve?ref=sparq-org/sparq/sparql-formal-semantics GET https://markdownregistry.com/api/v1/blob/7ceaaec34531353f553ab95d4f6eaa051c8b16e67b054ef0646f81e33ffa6b03
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