Let $X\rightarrow Y$ a ramified double cover of smooth projective curves, and let $$\mathcal G:=Res\_{X/Y}(SL\_n)$$
be the Weil restriction of the constant group scheme $SL\_n$ over $X$.



> 
> Question: Is $\mathcal G$ flat over $Y$ ?
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> 


N.B: I know (c.f. Néron Models) that $\mathcal G$ is flat over $Y$ if the cover is étale. 



Flatness of Weil restriction
As in the commentry of of @nfdc23, $\mathcal G$ is even smooth. Ref: Néron Models, Prop. 5 of section 7.6.


