Alignment Is Not a Match

Creation and merge each keep a clock. Even when the totals of new proposals and merges agree, they are only two aligned columns. Alignment is not a match: an older proposal may merge now, while a new one continues waiting.

Here, sets are more useful than subtraction. Match object identities before asking which problems reached a conclusion. A tidy total makes a convenient chart; a table that preserves identity can answer what happened next.