Hi! This bit of LaTeX gives me two curly brackets and a dollar sign that I didn't intend to put in. I don't know how to get rid of them. Can anybody help?

$\displaystyle \{\tau _1}{\text{ consists of }}\{\mathbb{R}}{\text{, }}\emptyset {\text{ and every interval }}\left( {a,b} \right){\text{ for }}a{\text{ and }}b{\text{ any real numbers with }}a < b{\text{;}}\$

Thanks!