 Speaker:

Prof. Manfred Droste

Title: 
Universal homogeneous causal sets 
Abstract: 
Causal sets are particular partially ordered sets which have been
proposed as a basic model for discrete spacetime in quantum gravity.
We show that the class C of all countable pastfinite causal sets
contains a unique causal set (U,<) which is universal (i.e., any
member
of C can be embedded into (U,<)) and homogeneous (i.e., (U,<)
has maximal degree of symmetry). Moreover, we give a probabilistic
construction of causal sets which produces, with probability 1,
a causal set isomorphic to (U,<). Moreover, (U,<) can also be
constructed explicitly. In contrast, we show that the class of all
countable causal sets does not contain a universal object.

Talk: 
Transparencies, Recorded Talk

 