PhD Seminar • Symbolic Computation • Applications of the Smith Massager of a Nonsingular Integer Matrix

Friday, September 10, 2021 10:00 am - 10:00 am EDT (GMT -04:00)

Please note: This PhD seminar will be given online.

Stavros Birmpilis,PhD candidate
David R. Cheriton School of Computer Science

Supervisors: Professors George Labahn, Arne Storjohann

Given a nonsingular integer matrixA ∈ Z×with Smith normal formS= diag(s1, . . . ,sn), we define a matrixM ∈ Z×to be a Smith massager forA. We use the notationcǻSto show that an equivalence is taken column modulo the diagonal entries inS. MatrixMsatisfies (i) thatAM≡ 0cǻS, namely, the matrix AMS−1is integral, and (ii) that there exists a matrixW∈ Z×such thatWM ≡ IncǻS, namely, the Smith massager is “unimodular” up to equivalence column moduloS. We obtain the Smith massager from an algorithm that computes the Smith form ofA. We show thatMserves as a useful object for tackling other problems in integer linear algebra like computing the Smith multiplier matrices forAor representing the fractional part of the adjoint ofA.


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