= Alexander module of a space
{c}
{title2=$H_1(\widetilde X_\alpha;\mathbb Z)$}
Given an integral epimorphism $\alpha:\pi_1(X)\to\mathbb Z$, the Alexander module is the first integral <homology> of the corresponding <infinite cyclic cover associated to an epimorphism>, with $t$ acting by its chosen <deck transformation>. Its order is the greatest common divisor of maximal presentation <matrix minors> when it is finitely presented and torsion. For the meridional epimorphism of a <knot exterior>, this is the <Alexander module of a knot>.
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