As the question title says, is the product of spheres $S^2 \times S^2$ diffeomorphic to the set of oriented $2$ dimensional vector subspaces of $\mathbb{R}^2$?
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$S^2\times S^2$ is the Grassmannian of $2$-planes in $R^4$, that is the set of oriented two planes of $R^4$ not of $R^2$.
See a proof here $S^2 \times S^2$ is diffeomophic to $G_2(\mathbb{R}^4)$
Tsemo Aristide
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