[Math] Writing a Permutation as a product of Disjoint Cycles

abstract-algebrapermutations

Write the following as a product of disjoint cycles:

$(1 3 2 5 6)(2 3)(4 6 5 1 2)$

I know from my solutions guide that the answer is:

$(1 2 4)(3 5)(6)$

but I don't know how to do that. I started by writing it as a product of transpositions as such:

$(1 3)(3 2)(2 5)(5 6)(2 3)(4 6)(6 5)(5 1)(1 2)$

I want to put this in standard form, but I don't know where to go from here…If anyone could help shed light on the procedure to do this, it would be very helpful.

Best Answer

First write this product with one permutation and then into product of disjoint cycles:

$$(1 3 6)(1357) (1234)= \left(\begin{matrix}1&2&3&4&5&6\\ 2&4&5&1&3&6\end{matrix}\right)=(1 2 4)(3 5).$$