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Equation 33 · Part 2 · The Entry a Relabeling Cannot Write

subscript

HfH_f
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

That “if and only if” is the whole of the construction’s ambition and the whole of its restraint. It does not propose that HfH_f or HcH_c is wrong, does not touch the total energy of any closed system, and does not by itself explain where a nonzero reading comes from; it only names, precisely and checkably, how large the disagreement is between two fully specified descriptions. Whether that disagreement is real, benign, or a mistake in bookkeeping is the question the rest of this article works through.

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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.