# Function is Borel measurable

## Homework Statement

Prove that the function $\phi(t)=t^{-1}$ is Borel measurable.

## Homework Equations

Any measurable function into $(\mathbb{R},\mathcal{B}(\mathbb{R}))$, where $\mathcal{B}(\mathbb{R})$ is the Borel sigma algebra of the real numbers $\mathbb{R}$, is called a Borel measurable function

## The Attempt at a Solution

I think I need to prove that t^{-1} is a Borel set, and so prove that it is open? I am quite unclear on the actual definition of a borel measurable function, and that is perhaps my problem.

## The Attempt at a Solution

Related Calculus and Beyond Homework Help News on Phys.org
morphism