The paper addresses one of nontrivial octonion related facts. According to
paper gr-qc/0409095, the most stable space-time state is the one described by
real Dirac matrices in 11-dimensional space of signature 1(-)&10(+). The
internal subspace is 7-dimensional, and its stability is due to a high ``zero''
energy packing density when using an oblique-angled basis from fundamental
vectors of lattice E_8 for the spinor degrees of freedom. The nontrivial fact
consists in the following: Dirac symbols with octonion matrix elements can be
used to describe states of the space of internal degrees of freedom if and only
if the space corresponds either to stable vacuum states or states close to the
just mentioned ones. The coincidence of the internal space dimension and
signature for absolutely different and independent approaches to the
consideration of this issue seems to predetermine the internal space vacuum
properties and the apparatus, which is able to constitute the basis of the
unified interaction theory.