Abstract
We construct and characterise a 3-homogeneous but not 2-primitive permutation group H of countable degree. It has a transitive extension J which is 5-homogeneous but not 3-primitive; the number nk(J) of orbits of J on k-sets is the number of boron trees with k end-vertices. Some groups related to other classes of trees are also constructed. An application to the growth rate of (nk(G)) for primitive groups G is given.
Original language | English |
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Pages (from-to) | 238-247 |
Number of pages | 10 |
Journal | Journal of the London Mathematical Society |
Volume | S2-27 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1 Jan 1983 |