The One Convention Everything Rests On
Each item on a list is counted as a separate coin. That is a unit of measurement, not a claim about anybody, and every figure on this site depends on it.
Reference
Fifty notes on what a list of requirements admits
Halving
A list whose items must all be met halves its own intake with each one added.
Part one
Each item on a list is counted as a separate coin. That is a unit of measurement, not a claim about anybody, and every figure on this site depends on it.
Reference
The first item on a list throws away half the possibility space. It is the largest single cut any item will ever make, and it is the one nobody thinks about.
Analysis
The full table of compulsory-only lists, from one item to eight. Nine shapes, nine powers of two, and no exceptions anywhere in the sequence.
Reference
Eight compulsory items admit one profile in two hundred and fifty-six. The eighth line is the one that gets argued about and the one that changes least.
Analysis
The halving law holds precisely, for every compulsory item, with no exceptions anywhere in the record. The proof fits in a paragraph and is worth having.
Reference
Compulsory items commute. The order they were written in leaves no trace in the result — obvious in arithmetic, and persistently untrue in how lists get read.
Analysis
Adding a line costs the author nothing and costs the filter half of everything. The asymmetry is structural, and it explains how lists reach eight items.
Analysis
Eight compulsory and eight optional items is where the enumeration ends. The bound is a choice, it is stated rather than implied, and nothing new lies past it.
Reference
What the arithmetic lets a reader work out about a list in front of them, and the much longer list of things it does not.
Analysis