How Is Compression Prediction?
Over the past few weeks, I have repeatedly encountered the same claim on Hacker News: compression is prediction. The recent discussion has approached it from both directions. Two 3Blue1Brown videos, Reinventing Entropy and But what is cross-entropy?, derive entropy and cross-entropy from the limits of source coding.
- ▪Over the past few weeks, I have repeatedly encountered the same claim on Hacker News: compression is prediction.
- ▪The recent discussion has approached it from both directions.
- ▪Two 3Blue1Brown videos, Reinventing Entropy and But what is cross-entropy?, derive entropy and cross-entropy from the limits of source coding.
Hacker News (Front Page) files mainly under programming. We currently carry 1,590 of its stories. Top-voted stories on Hacker News.
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Story provenance
Attribution is not the same as permission. This drawer separates discovery metadata, excerpts, WeSearch-generated summaries, reuse status, and whether the publisher receives the visit. Nothing here claims a legal grant the publisher has not made.
Record
| Original publisher | Hacker News (Front Page) |
| Canonical URL | https://lukefleed.xyz/posts/compression/ |
| Publication time | Mon, 14 Sep 2026 10:22:33 +0000 |
| Retrieval time | 2026-09-14T10:51:52.005Z |
| Last seen | 2026-09-14T10:51:52.005Z |
| Headline source | Publisher (no WeSearch rewrite) |
| Excerpt source | publisher body |
| Excerpt method | First ~120 words (~800 chars) of extracted publisher body, fair-use limited. |
| Summary | WeSearch · cerebras-chat (WeSearch summarizer) |
| Summary source text | contentText |
| Citation coverage | Summary is a WeSearch-generated derivative; primary citation is the original publisher URL. |
| Cluster | InI-b7bk-Bmo · 1 stories |
| Cluster logic | Grouped by semantic title/content similarity across sources within a rolling window. Same-publisher template collisions are excluded from coverage comparison. |
| Ranking reason | Story pages are not engagement-ranked. Hub feeds use recency, with optional source-diversified chronological ordering (cap consecutive stories per source). No personalized ranking. |
| Publisher visit | Yes — open original |
| Substitutes article? | No — link-out required for full text |
Rights status (four layers)
WeSearch handling by dimension
| Indexing | May the item be indexed (stored, ranked, made findable)? | Allowed |
| Snippet | May a short excerpt of the publisher's text be shown? | Allowed |
| AI summary | May WeSearch generate its own short summary of the article? | Limited |
| Retrieval / RAG | May the content be exposed for third-party retrieval-augmented generation? | Not asserted |
| Model training | May the content be used to train AI models? | Not asserted |
| Commercial reuse | May the content be reused commercially? | Not permitted |
Basis: Derived from the published RSS/Atom feed. Contact: [email protected]. Reviewed: 2026-07-24.
Opening excerpt (first ~120 words) tap to expand
Over the past few weeks, I have repeatedly encountered the same claim on Hacker News: compression is prediction. The recent discussion has approached it from both directions. Two 3Blue1Brown videos, Reinventing Entropy and But what is cross-entropy?, derive entropy and cross-entropy from the limits of source coding. An ngrok article follows the same mathematics through arithmetic coding and language models. Salvatore Sanfilippo asks how far the resulting identification between prediction and compression should be taken. These explanations meet at one fact. A probabilistic model assigns a conditional probability to every possible continuation, and an entropy coder converts the probability assigned to the observed continuation into bits.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at Hacker News (Front Page).
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