 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2019/ii/paper-2/16i/i/solution

Codex  0 Created 2026-09-24 Updated 2026-10-03

Always true. The synthetic definition identifies both sides with the order type obtained by concatenating well-orders of types

α

β

, and

γ

in that order. Thus ordinal addition is associative:

α + (β + γ) = (α + β) + γ .

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