Changeset f7d745 in git for Singular/LIB/jacobson.lib


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Timestamp:
May 26, 2011, 1:55:32 PM (13 years ago)
Author:
Hans Schoenemann <hannes@…>
Branches:
(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')
Children:
38ac8cadfce1628aa28008b1a3d9bbd297dd2983
Parents:
1fe2271e3800804bd9a9bef62db37a53fa11b38e
Message:
format

git-svn-id: file:///usr/local/Singular/svn/trunk@14246 2c84dea3-7e68-4137-9b89-c4e89433aadc
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1 edited

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  • Singular/LIB/jacobson.lib

    r1fe227 rf7d745  
    99OVERVIEW:
    1010We work over a ring R, that is an Euclidean principal ideal domain.
    11 @* If R is commutative, we suppose R to be a polynomial ring in one variable.
    12 @* If R is non-commutative, we suppose R to have two variables, say x and d.
    13 @* We treat then the basering as the Ore localization of R
    14 @* with respect to the mult. closed set S = K[x] without 0.
    15 @* Thus, we treat basering as principal ideal ring with d a polynomial
    16 @* variable and x an invertible one.
    17 @* Note, that in computations no division by x will actually happen.
    18 @*
    19 @* Given a rectangular matrix M over R, one can compute unimodular (that is
    20 @* invertible) square matrices U and V, such that U*M*V=D is a diagonal matrix.
    21 @* Depending on the ring, the diagonal entries of D have certain properties.
    22 @*
    23 @* We call a square matrix D as before 'a weak Jacobson normal form of M'.
    24 @* It is known, that over the first rational Weyl algebra K(x)<d>, D can be further
    25 @* transformed into a diagonal matrix (1,1,...,1,f,0,..,0), where f is in K(x)<d>. We call
    26 @* such a form of D the strong Jacobson normal form. The existence of strong form
    27 @* in not guaranteed if one works with algebra, which is not rational Weyl algebra.
     11If R is commutative, we suppose R to be a polynomial ring in one variable.
     12If R is non-commutative, we suppose R to have two variables, say x and d.
     13We treat then the basering as the Ore localization of R
     14with respect to the mult. closed set S = K[x] without 0.
     15Thus, we treat basering as principal ideal ring with d a polynomial
     16variable and x an invertible one.
     17Note, that in computations no division by x will actually happen.
     18
     19Given a rectangular matrix M over R, one can compute unimodular (that is
     20invertible) square matrices U and V, such that U*M*V=D is a diagonal matrix.
     21Depending on the ring, the diagonal entries of D have certain properties.
     22
     23We call a square matrix D as before 'a weak Jacobson normal form of M'.
     24It is known, that over the first rational Weyl algebra K(x)<d>, D can be further
     25transformed into a diagonal matrix (1,1,...,1,f,0,..,0), where f is in K(x)<d>.
     26We call such a form of D the strong Jacobson normal form.
     27The existence of strong form in not guaranteed if one works with algebra,
     28which is not rational Weyl algebra.
    2829
    2930
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