Equation 4 · Part 3 · The Hardest Unsolved Problems in Evaluating xAI's Claims
subscript
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.
Full expression→subscript→Article meaning
The passage around this formula
giving 3.16 , = 10 , and 31.6 — which is a formal way of saying that even a well-resourced independent estimate of a frontier training run can be off by an order of magnitude or more, and everyone doing the estimating knows it going in. Epoch’s own account of its Grok 4 figures is direct about why: “the FLOP and GPU-hour estimates for Grok-4 are largely based on public statements from xAI, which are often vague,” producing significant uncertainty in the resulting compute total [ 4 ] . Their published point estimate — roughly 5.0×10²⁶ FLOP, built from about 246 million H100-hours — is a best reconstruction, not a confirmed figure, and Epoch says so on the page.
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 surrounding passage
These citations provide research context; check each source for the exact claim it supports.