What is $\Bbb R^{\times}$? [unit group, ring to "times" power] I'm doing some sheets for my Abstract Algebra class and I can't seem to remember the group defined as $\mathbb{R}^{\times}$. It's obviously some variation of $\mathbb{R}$ but I'm away from college on reading week so can't ask my tutor. If someone could clear up the confusion I'd be grateful.

The notation is often used on the form $\Bbb R^*$ i.e. with a star and it means $\Bbb R\setminus \{0\}$ and we have $(\Bbb R^*,\times)$ is a multiplicative  group.
