Imagine that we attach a label to each elementary particle in the Universe, each label having a unique natural number ... In this model, everything who can be send in past is represented a series of labels. If a thing is sent back in time...a phone for exemple (we assume that it contains the elementary particles with the numbers 7 and 1003) then we will find in the past, simultaneously these elementary particles twice, in the same Universe and at the same time. Do you think it is possible?