Changeset 0b59f5 in git for Singular/LIB/homolog.lib


Ignore:
Timestamp:
Dec 13, 1999, 4:33:50 PM (24 years ago)
Author:
Olaf Bachmann <obachman@…>
Branches:
(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')
Children:
82ed244cff3158b7a79a6eed4e0548d485960cfe
Parents:
925cab8e04ecb2f3c2e451b913c11bcac28b2374
Message:
* GMG's changes


git-svn-id: file:///usr/local/Singular/svn/trunk@4006 2c84dea3-7e68-4137-9b89-c4e89433aadc
File:
1 edited

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  • Singular/LIB/homolog.lib

    r925cab r0b59f5  
    1 // $Id: homolog.lib,v 1.9 1999-08-03 11:43:06 obachman Exp $
     1// $Id: homolog.lib,v 1.10 1999-12-13 15:33:47 obachman Exp $
    22//(BM/GMG)
    33///////////////////////////////////////////////////////////////////////////////
    44
    5 version="$Id: homolog.lib,v 1.9 1999-08-03 11:43:06 obachman Exp $";
     5version="$Id: homolog.lib,v 1.10 1999-12-13 15:33:47 obachman Exp $";
    66info="
    77LIBRARY:  homolog.lib   PROCEDURES FOR HOMOLOGICAL ALGEBRA
     
    554554         0<--M'<-- F0 <-M-- F1 <-- F2 <--...  resp. 0<--N'<-- G0 <--N- G1 be
    555555         a free resolution of M' resp. a presentations of N'. Consider
     556@format
    556557                      0                  0                  0
    557558                      |^                 |^                 |^
     
    562563                                         |C                 |B
    563564                                      Hom(Fk,G1) -----> Hom(Fk+1,G1)
     565@end format
    564566         (Ak,Ak+1 induced by M and B,C induced by N).
    565567         Let K=modulo(Ak+1,B), J=module(Ak)+module(C) and Ext=modulo(K,J),
     
    568570         R^q -Ext-> R^p --K->Hom(Fk,G0)/im(Ak)+im(C) --Ak+1->Hom(Fk+1,G0)/im(B)
    569571         Hence Ext presents Ext^k(M',N')
    570 RETURN:  Ext, of type module, a presentation of Ext^k(M',N') if v is of type
     572RETURN: 
     573         Ext, of type module, a presentation of Ext^k(M',N') if v is of type
    571574         int, resp. a list of Ext^k (k=v[1],v[2],...) if v is of type intvec.
    572575         In case of a third argument of any type return a list:
     
    715718         Let ...-->F1 --M-> F0-->M'-->0 and ...-->G1 --N-> G0-->N'-->0  be
    716719         presentations of M' and N'. Consider
     720@format
    717721                                         0               0
    718722                                         |^              |^
     
    728732              R^q -Hom-> R^p --D-> Hom(F0,G0)/im(C) --A-> Hom(F1,G0)/im(B).
    729733         Hence Hom presents Hom(M',N')
     734@end format
    730735RETURN:  Hom, of type module, presentation of Hom(M',N') or,
    731736         in case of 3 arguments, a list:
     
    845850         (R=basering) and let A:R^m-->R^n a matrix inducing a map A':M'-->N'.
    846851         Compute a presentation K of ker(A') as in the commutative diagram:
     852@format
    847853                       ker(A') --->  M' --A'--> N'
    848854                           |^        |^         |^
     
    853859                           |         |          |
    854860                          R^s  ---> R^p -----> R^q
     861@end format
    855862RETURN:  module K, a presentation of ker(A')
    856863EXAMPLE: example kernel; shows examples
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