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Real geometric algebras distinguish between space and time; complex ones do not. Space-times can be classified in terms of number n of dimensions and metric signature s (number of spatial dimensions minus number of temporal dimensions). Real geometric algebras are periodic in s, but recursive in n. Recursion starts from the basis vectors of either the Euclidean plane or the Minkowskian plane. Although the two planes have different geometries, they have the same real geometric algebra. The direct product of the two planes yields Hestenes’ space-time algebra. Dimensions can be either open (for space-time) or closed (for the electroweak force). Their product yields the eight-fold way of the strong force. After eight dimensions, the pattern of real geometric algebras repeats. This yields a spontaneously expanding space-time lattice with the physics of the Standard Model at each node. Physics being the same at each node implies conservation laws by Noether’s theorem. Conservation laws are not pre-existent; rather, they are consequences of the uniformity of space-time, whose uniformity is a consequence of its recursive generation. [ABSTRACT FROM AUTHOR]

This article carries out the investigation to obtain the condition under which the generalized Z -recurrent spacetimes (briefly, G Z 4 spacetimes) become a perfect fluid spacetime. It is shown that in a G Z 4 spacetime obeying Codazzi type and cyclic parallel Z tensor represents a perfect fluid spacetime, provided the basic vector fields are co-directional. Next, we prove that a conformally flat G Z 4 spacetime represents the dark matter era under certain conditions. We also characterize the perfect fluid Ricci symmetric G Z 4 spacetimes. Moreover, we investigate perfect fluid G Z 4 spacetimes in f (R , T) -gravity theory. [ABSTRACT FROM AUTHOR]