Every $3$-manifold with boundary embeds in ${\rm Triod}\times {\rm Triod}\times I$

Zhong Mou Li
1994 Proceedings of the American Mathematical Society  
Let M be a compact, connected 3-manifold with nonempty boundary. Then M embeds in T x T x /, where T is a triod and / = [0, 1].
doi:10.1090/s0002-9939-1994-1254861-4 fatcat:eb37mfqanrhvdgbux2igth3kla