De Sitter corresponded with Ehrenfest in 1916, and he proposed that a four- dimensional space- time would fit in with cosmological models based on general relativity.
Mula pasahero corresponded sa Ehrenfest sa 1916, siya at iminungkahi na ang isang apat na-dimensional space-time na magkasya sa may kosmolohiko modelo batay sa pangkalahatang kapamanggitan.