22 - Motivating Motives
Similarly, we have
$$ h(\mathbb{P}^n) \; \cong \; h(1) \; \oplus \; \mathbb{L} \; \oplus \; \mathbb{L}^{\otimes 2} \; \oplus \; \cdots \; \oplus \; \mathbb{L}^{\otimes n} $$
and this corresponds to the formula we saw for the number of points of \(\mathbb{P}^n\) over \(\mathbb{F}_q\):
$$ 1 \; + \; q \; + \; \cdots \; + \; q^n $$
But curves and other varieties typically decompose into motives
that are not just tensor powers of the Lefshetz motive \(\mathbb{L}\).