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Pedro Passos

Publications and source records attributed to Pedro Passos.

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Prescriptive Artificial Intelligence: A Formal Paradigm for Auditing Human Decisions Under Uncertainty

We formalize Prescriptive Artificial Intelligence as a distinct paradigm for human-AI decision collaboration in high-stakes, stochastic environments involving single-agent individual decision-making. Unlike predictive systems optimized for outcome accuracy, prescriptive systems audit human decisions under uncertainty, providing normative guidance while preserving human agency and accountability. We introduce four domain-independent axioms characterizing prescriptive systems and prove fundamental separation results. Central is the Imitation Incompleteness theorem: supervised learning from historical decisions cannot correct systematic biases in the absence of external normative signals. Under standard regularity conditions, the induced predictor converges almost surely to the biased action rather than the normatively optimal one. Performance in decision imitation is therefore bounded by a structural bias term (epsilon_bias) rather than the statistical rate O(1/sqrt(n)), a result extended to Markovian logs and finite-sample concentration bounds. We demonstrate realizability through three independent instantiations spanning five decades: an interpretable fuzzy system for elite soccer auditing, revealing decision latency and risk states obscured by outcome and status quo biases; MYCIN, the historically validated rule-based clinical consultation system; and NEWS2, a nationally mandated clinical protocol validated on a prospective multi-center cohort. The framework establishes Prescriptive AI as a general, realizable class of decision-support systems for safety-critical domains where interpretability, contestability, and normative alignment are essential.

cs.AI

Observing boson stars in binary systems: The case of Gaia BH1

The Gaia experiment recently reported the observation of a binary system composed of a Sun-like star orbiting a dark compact object, known as Gaia BH1. The nature of the compact object remains uncertain. While the Gaia mission identifies it as a black hole candidate, the absence of X-ray or radio detections challenges that interpretation, and alternative exotic compact objects such as boson stars have also been suggested. In this paper, we study whether a boson star could account for the observed properties of the source. To do so we compute the X-ray luminosity of the central dark object as a result of spherically symmetric (Bondi-Michel) accretion of matter, comparing our results for the cases in which the dark object is a Schwarzschild black hole or a non rotating boson star. Our model incorporates realistic interstellar medium properties, ranging from hot ionized gas to dense molecular clouds. By solving the governing equations numerically, we calculate mass accretion rates and derive the resulting Bremsstrahlung X-ray luminosities. Black holes and boson stars fundamentally differ by the absence of an event horizon in the latter, which directly impacts accretion dynamics as there is an accumulation of mass in regions closer to the boson star, which will significantly change the observed X-ray emission. For the Gaia BH1 system we find that accretion onto a black hole yields luminosities of $\sim10^{27} \ \text{erg}\, \text{cm}^{-2}\, \text{s}^{-1}$ which corresponds to an X-ray flux undetectable by Chandra sensitivity. On the other hand, boson star accretion can produce observable luminosities in the order of $10^{27} \ \text{to} \ 10^{41} \ \text{erg}\, \text{cm}^{-2}\, \text{s}^{-1}$.

astro-ph.HE