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In algebraic geometry, a homogeneous variety is an algebraic variety on which an algebraic group acts transitively.[1][2] Equivalently, it is a quotient variety G/H where G is an algebraic group and H an algebraic subgroup.[3]
Such varieties are always smooth projective varieties.
Classical examples are flag varieties (when G is semisimple and H a Borel subgroup) or more generally spherical varieties. Also toric varieties (when G is an algebraic torus).