= Hecke-normalized rational slash operator
{c}
{title2=$f[\alpha]_k=(\det\alpha)^{k-1}(c\tau+d)^{-k}f(\alpha\tau)$}
For a rational <matrix> of positive determinant, this slash normalization differs from the <determinant-normalized slash operator> by $(\det\alpha)^{k/2-1}$. Both are right actions, by the <automorphy factor> identity. For a positive scalar $t$, the displayed action of $tI$ is multiplication by $t^{k-2}$. On determinant-one matrices it agrees with the ordinary <slash operator for modular forms>. This normalization makes a good-prime <Hecke operator> a plain sum over its double-coset representatives.
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