Abstract
We show that, for each natural numberk, these exists a (smallest) natural numberf(k) such that any digraph of minimum outdegree at leastf(k) containsk disjoint cycles. We conjecture thatf(k)=2k−1 and verify this fork=2 and we show that, for eachk≧3, the determination off(k) is a finite problem.
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Dedicated to Paul Erdős on his seventieth birthday
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Thomassen, C. Disjoint cycles in digraphs. Combinatorica 3, 393–396 (1983). https://doi.org/10.1007/BF02579195
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AMS subject classification (1980)
- 05 C 20
- 05 C 38