 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2018/ii/paper-1/17i/b/solution

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

H

r + 1 \geq 2

, then

ex (n, H) = (1 - \frac{1}{r} + o (1)) (2 n) .

H

is a bipartite graph with at least one edge, its chromatic number is two, so

r = 1

and therefore

n \to \infty lim \frac{ex ( n , H )}{( 2 n )} = 0.

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