We prove that any element in the group generated by the Riordan involutions is the product of at most four of them. We also give a description of this subgroup as a semidirect product of a special subgroup of the commutator subgroup and the Klein four-group.

中文翻译：

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Riordan对合产生的组

我们证明了Riordan对合产生的组中的任何元素都是其中最多四个的乘积。我们还将这个子组描述为换向器子组和Klein四组的特殊子组的半直接乘积。