Problem #574: Is it true that, for $k\geq...

Is it true that, for $k\geq 2$,\[\mathrm{ex}(n;\{C_{2k-1},C_{2k}\})=(1+o(1))(n/2)^{1+\frac{1}{k}}.\]

SOLVED

Problem Statement

Is it true that, for $k\geq 2$,\[\mathrm{ex}(n;\{C_{2k-1},C_{2k}\})=(1+o(1))(n/2)^{1+\frac{1}{k}}.\]

Categories: Graph Theory Turan Number

A problem of Erdős and Simonovits.

See also [573] for the specific case of $k=2$ and the entry in the graphs problem collection.

Source: erdosproblems.com/574 | Last verified: January 15, 2026