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<p>-dimensional <a href="page.php?w=homotopy_group">homotopy group</a>  of a space  at the distinguished point  can be understood as the composition of  and  with :</p>

<p>Here,  are maps which take a distinguished point  to the point  Note that the above uses the wedge sum of two functions, which is possible precisely because they agree at  the point common to the wedge sum of the underlying spaces.</p>

<p><big>Categorical description</big></p>
<p>The wedge sum can be understood as the <a href="page.php?w=coproduct">coproduct</a> in the <a href="page.php?w=category_of_pointed_spaces">category of pointed spaces</a>.</p><p>
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