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Ultra‑Sparse Embeddings Without Apology

Opening — Why this matters now Embeddings have quietly become the metabolic system of modern AI. Every retrieval query, recommendation list, and ranking pipeline depends on them—yet we keep feeding these systems increasingly obese vectors. Thousands of dimensions, dense everywhere, expensive always. The paper behind CSRv2 arrives with an unfashionable claim: you can make embeddings extremely sparse and still win. ...

February 8, 2026 · 3 min · Zelina
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Beyond Cosine: When Order Beats Angle in Embedding Similarity

Opening — Why this matters now Cosine similarity has enjoyed an unusually long reign. From TF‑IDF vectors to transformer embeddings, it remains the default lens through which we judge “semantic closeness.” Yet the more expressive our embedding models become, the more uncomfortable this default starts to feel. If modern representations are nonlinear, anisotropic, and structurally rich, why are we still evaluating them with a metric that only understands angles? ...

February 7, 2026 · 4 min · Zelina
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When Agents Loop: Geometry, Drift, and the Hidden Physics of LLM Behavior

Opening — Why this matters now Agentic AI systems are everywhere—self-refining copilots, multi-step reasoning chains, autonomous research bots quietly talking to themselves. Yet beneath the productivity demos lurks an unanswered question: what actually happens when an LLM talks to itself repeatedly? Does meaning stabilize, or does it slowly dissolve into semantic noise? The paper “Dynamics of Agentic Loops in Large Language Models” offers an unusually rigorous answer. Instead of hand-waving about “drift” or “stability,” it treats agentic loops as discrete dynamical systems and analyzes them geometrically in embedding space. The result is less sci‑fi mysticism, more applied mathematics—and that’s a compliment fileciteturn0file0. ...

December 14, 2025 · 4 min · Zelina
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Words + Returns: Teaching Embeddings to Invest in Themes

How do you turn a fuzzy idea like “AI + chips” into a living, breathing portfolio that adapts as markets move? A new framework called THEME proposes a crisp answer: train stock embeddings that understand both the meaning of a theme and the momentum around it, then retrieve candidates that are simultaneously on‑theme and investment‑suitable. Unlike static ETF lists or naive keyword screens, THEME learns a domain‑tuned embedding space in two steps: first, align companies to the language of themes; second, nudge those semantics with a lightweight temporal adapter that “listens” to recent returns. The result is a retrieval engine that feeds a dynamic portfolio constructor—and in backtests, it beats strong LLM/embedding baselines and even average thematic ETFs on risk‑adjusted returns. ...

August 26, 2025 · 5 min · Zelina