Symbol Δ P
Δ P is part of the quantity the equation computes from the expression on the right.
Read this term in its guide →Published equation contexts
Why this formula appears here
For most of the period in which Europeans kept parish records, the largest towns buried more people than they baptised. Population still rose, which means the arithmetic was closed from outside. The identity is trivial but it is worth writing down, because almost every disagreement in this field is a disagreement about one of its terms: . Population change in a city equals natural increase, births minus deaths, plus net in-migration. The urban graveyard claim is the specific and testable assertion that for long stretches the first bracket was negative while the sum was positive: cities grew, and grew only because the countryside kept sending replacements.
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Symbol B
B is one of the signed contributions combined to compute the quantity on the left.
Read this term in its guide →Symbol D
D is one of the signed contributions combined to compute the quantity on the left.
Read this term in its guide →Symbol M
M is one of the signed contributions combined to compute the quantity on the left.
Read this term in its guide →How to interpret it
Read it with the definitions, units, and assumptions supplied by the article.
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Published contexts (1)
A symbol can carry a different meaning in another article. Each occurrence keeps its own guide and term definitions.
Equation 1 · Demography & Urbanization
Water Before Demography
This equation states an equality: the expressions on both sides have the same value under the article’s assumptions.
For most of the period in which Europeans kept parish records, the largest towns buried more people than they baptised. Population still rose, which means the arithmetic was closed from outside. The identity is trivial but it is worth writing down, because almost every disagreement in this field is a disagreement about one of its terms: . Population change in a city equals natural increase, births minus deaths, plus net in-migration. The urban graveyard claim is the specific and testable assertion that for long stretches the first bracket was negative while the sum was positive: cities grew, and grew only because the countryside kept sending replacements.
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