A breakthrough October 2004 paper by Omer Reingold showed that USTCON is in fact in L. Since USTCON is SL-complete, this implies that SL = L, essentially eliminating the usefulness of consideration of SL as a separate class. A few weeks later, graduate student Vladimir Trifonov showed that USTCON could be solved deterministically using O(log "n" log log "n") space—a weaker result—using different techniques. There has not been substantial effort into turning Reingold's algorithm for USTCON into a practical formulation. It is explicit in his paper (and those leading up to it) that they are primarily concerned with asymptotics; as a result, the algorithm he describes would actually take formula_2 memory, and formula_3 time. This means that even for formula_4, the algorithm would require more memory than contained on all computers in the world (a kiloexaexaexabyte).