Let $X$ in $(\Omega, \mathfrak{F}_1,P_1)$ and $Y$ in $(\Omega, \mathfrak{F}_2,P_2)$ two real random variables such that $X=Y$ in distribution.
The question is:
The $\sigma$-algebras $\sigma_{X}:=\{ A\in \mathfrak{F}_1: A=X^{-1}(B),\mbox{ for all } B\in\mathfrak{B}(\mathbb{R}) \}$ and $\sigma_{Y}$ generated by $X$ and $Y$ are the same?
I think the answer is not, in the case $P_{1} \neq P_2$, but I need to show a counterexample of this.
And in the case $P_1=P_2$ I don't know. Maybe is truth.