  Consider the neutral Tannakian category mixed Tate motives over Z, in this
paper we suggest a way to understand the structure of depth-graded motivic Lie
subalgebra generated by the depth one part. We will show that from an
isomorphism conjecture proposed by K. Tasaka we can deduce the F. Brown matrix
conjecture and the non-degenerated conjecture about depth-graded motivic Lie
subalgebra generated by the depth one part.
