EN
Poincaré's classical recurrence theorem is generalised to the noncommutative setup where a measure space with a measure-preserving transformation is replaced by a von Neumann algebra with a weight and a Jordan morphism leaving the weight invariant. This is done by a suitable reformulation of the theorem in the language of $L^{∞}$-space rather than the original measure space, thus allowing the replacement of the commutative von Neumann algebra $L^{∞}$ by a noncommutative one.