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Equation 6 · Part 11 · How Constitutional AI Actually Constrains a Model's Behavior

subscript

LPM(θ)=− E(x, yw, yl) ∼ DH∪DAI[log⁡σ(rθ(x,yw)−rθ(x,yl))].\mathcal{L}_{PM}(\theta) = -\,\mathbb{E}_{(x,\,y_w,\,y_l)\,\sim\, D_H \cup D_{AI}}\Big[\log \sigma\big(r_\theta(x,y_w) - r_\theta(x,y_l)\big)\Big].
subscript

What this part means

The lower label selects a particular version, component, or indexed member of the quantity. For example, x₀ and xₜ can be values at different positions.

Its job in the formula

A subscript distinguishes a version, component, step, or member of a quantity. It does not automatically mean multiplication.

The passage around this formula

Crucially, this AI-generated harmlessness comparison data did not replace human comparison data outright; it was combined with it. The paper reports 135,296 human helpfulness comparisons and 182,831 constitutionally generated harmlessness comparisons feeding one preference model, trained on the union of both, in the authors’ words: “we use human labels for helpfulness, but only AI labels for harmlessness.” A single Bradley-Terry-style preference loss is fit across both sources at once. Writing DHD_H for the human comparison set, DAID_{AI} for the AI-generated set, rθr_\theta for the reward model, x for a prompt, and ywy_w, yly_l for the winning and losing response in a pair, the objective is [displayed…

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

Open the illustrated subscripts: which member of a family? guide →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.