Measurability at Planck’s scales, coherence loss, and black holes quantum entropy

It is noted that in the quantum theory at Planck’s scales (Early Universe), with introduction of the fundamental length, the measuring procedure is changed, leading to the density-matrix deformation. This deformation is described explicitly, and its inferences may be used for the determination of pure and mixed states in the associated quantum mechanics, for Hawking’s Problem solution in case of the coherence loss on black hole evaporation, and in calculations of the black hole quantum entropy. The text was submitted by the author in English.