The Product of Nonplanar Complexes does not Imbed in 4-Space

Brian R. Ummel
1978 Transactions of the American Mathematical Society  
We prove that if Kx and K2 are nonplanar simplicial complexes, then Kx X K2 does not imbed in R4.
doi:10.2307/1997741 fatcat:22jqxf4sb5g2ler53nal4umtqm