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Calling Sequence
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IsCPGroup( G )
IsCP1Group( G )
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Parameters
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Description
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A group is a (CP)-group if each of its elements has prime-power order, where the prime may depend upon the element. A group of prime-power order is a (CP)-group, but there are (CP)-groups, such as , whose order is divisible by more than one prime. This is equivalent to the condition that the centralizer of each non-trivial element is a -group, for some prime depending upon the element. It is also equivalent for finite groups to the Gruenberg-Kegel graph of the group being totally disconnected.
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A group is a (CP1)-group if each of its non-trivial elements has prime order where, again, the prime may depend upon the element. Equivalently, a group is a (CP1)-group if the centralizer of each non-trivial element contains only elements of order dividing , for a prime depending upon the element. The symmetric group is again an example of a (CP1)-group not of prime exponent.
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It is a consequence of these definitions that every (CP1)-group is a (CP)-group. Both (CP)-groups and (CP1)-groups are (CN)-groups.
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The IsCPGroup( G ) command returns true if the group G is a (CP)-group and returns false otherwise.
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The IsCP1Group( G ) command returns true if the group G is a (CP1)-group and returns false otherwise.
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Examples
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The symmetric group furnishes an example of a (CP)-group that is not a group of prime power order, and a (CP1)-group that is not of prime exponent.
The symmetric group is also a (CP)-group, but symmetric groups of larger degree are not. However, is not a (CP1)-group.
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A cyclic group is a (CP)-group if, and only if, it has prime power order.
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| (8) |
And cyclic groups are (CP1)-groups precisely when the order is a prime.
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Dihedral groups are (CP)-groups just when the degree is a prime power.
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And, dihedral groups of prime degree are the only ones that are (CP1)-groups.
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Groups of prime exponent are (CP1)-groups.
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| (17) |
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| (20) |
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The group is the Frobenius group of order and is a (CP)-group.
Other Frobenius groups provide important examples of (CP)-groups.
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These are all the simple (CP)-groups (M. Suzuki).
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The only simple (in fact, the only insoluble) (CP1)-group is the alternating group .
An example of an infinite (CP)-group.
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