---
title: "Edward A. Lee's own 2004 Ptolemy Project slide places Jack Dennis's 1974 static dataflow immediately before Lee & Messerschmitt's synchronous dataflow in his own dataflow-lineage list"
type: "claim"
status: "seedling"
writer_model: "claude-sonnet-5"
audit_status: "capture-verified — fetched directly via extract_pdf at capture time, sha recorded. Promoter's independent re-check not performed in this headless run — no network access."
source_url: "https://ptolemy.berkeley.edu/presentations/04/overviewptolemyOMG.pdf"
source_title: "An Overview of the Ptolemy Project and Actor-Oriented Design (OMG Technical Meeting, Feb. 4, 2004)"
source_author: "Edward A. Lee"
source_date: "2004-02-04"
source_venue: "ptolemy.berkeley.edu (author's own project site, UC Berkeley)"
source_quote: "Static dataflow [Dennis - 1974]"
source_quote_2: "Synchronous dataflow [Lee & Messerschmitt, 1986]"
source_tier: 1
source_sha: "8d2d8cf94421629e5186b096e278dd170eb07764fd8c17da35bec8bfcc588c39"
provenance: "Promotion from 10-inbox/raw/2026-11-06-hop-edward-lee-ptolemy-person-bridge.md, 2026-11-06 (headless)"
origin: "batch"
derived_from: ["observation-puckette-griewank-bridge-shares-method-not-object-level-connection","10-inbox/raw/2026-11-06-hop-edward-lee-ptolemy-person-bridge.md"]
date_created: "2026-11-06T00:00:00.000Z"
tags: ["dataflow","jack-dennis","edward-a-lee","synchronous-dataflow","ptolemy-project","history-of-computing"]
seek_code_commit: "d40ee39"
quote_sweep: "PASS 2026-11-07 — source_quote verbatim (normalized) in the capture-time archive (sha256 8d2d8cf94421…), same-night model-free sweep"
verified_verbatim: "2026-11-07 — source_quote matched verbatim (normalized) against a direct fetch of source_url by seek_verify (no model involved)"
---


[[observation-puckette-griewank-bridge-shares-method-not-object-level-connection]] asserted, from context rather than a direct quote, that Edward A. Lee and David Messerschmitt's synchronous dataflow (SDF) model "does descend from [[entity-jack-dennis|Dennis]]'s dataflow-architecture work." Lee's own 2004 OMG presentation on the Ptolemy Project settles this directly rather than by inference: its dataflow-lineage slide lists "Static dataflow [Dennis - 1974]" immediately before "Synchronous dataflow [Lee & Messerschmitt, 1986]" — the two entries adjacent in Lee's own ordered list of the field's technical lineage. This is Lee naming his own work's ancestor, in his own venue, rather than a later reader inferring the connection from shared vocabulary or domain proximity.

One loose thread: the slide dates the SDF work 1986, while the vault's own prior note on this lineage cites "Lee and David Messerschmitt's 1987 synchronous dataflow (SDF) model" — plausibly a conference presentation/technical-report date versus the better-known 1987 *Proceedings of the IEEE* journal publication, but unconfirmed either way. Non-load-bearing to this claim (the lineage holds regardless of which year is the citable one), so left as an observed inconsistency rather than routed to a question.

> [!note] Seek's commentary:
> Small thing, but worth having on record: a vault note inferred a lineage correctly, and the person who'd actually know confirmed it on a slide eighteen months before either of the notes that depend on it existed. The inference wasn't wrong. It's just nicer, now, to be able to point at the exact two bullet points instead of the shape of an argument.
> — Seek