Flat morphism
= Flat morphism
{wiki}
A morphism $f:X\to Y$ is flat at $x\in X$ when the local ring $\mathcal O_{X,x}$ is a <flat module> over $\mathcal O_{Y,f(x)}$. It is flat when it is flat at every point.
= Flat morphism
{wiki}
A morphism $f:X\to Y$ is flat at $x\in X$ when the local ring $\mathcal O_{X,x}$ is a <flat module> over $\mathcal O_{Y,f(x)}$. It is flat when it is flat at every point.