# nLab rational cohomology

Contents

### Context

#### Rational homotopy theory

and

rational homotopy theory

cohomology

# Contents

## Idea

By rational cohomology one usually means ordinary cohomology with rational number coefficients, denoted $H^\bullet\big(-, \mathbb{Q}\big)$.

Hence, with the pertinent conditions on the domain space $X$ satisfied, its rational cohomology $H^\bullet\big(-, \mathbb{Q}\big)$ is what is computed by the Cech cohomology or singular cohomology or sheaf cohomology of $X$ with coefficients in $\mathbb{Q}$.

Last revised on October 6, 2019 at 10:18:13. See the history of this page for a list of all contributions to it.