Changeset 0b59f5 in git for Singular/LIB/homolog.lib
- Timestamp:
- Dec 13, 1999, 4:33:50 PM (24 years ago)
- Branches:
- (u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')
- Children:
- 82ed244cff3158b7a79a6eed4e0548d485960cfe
- Parents:
- 925cab8e04ecb2f3c2e451b913c11bcac28b2374
- File:
-
- 1 edited
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Singular/LIB/homolog.lib
r925cab r0b59f5 1 // $Id: homolog.lib,v 1. 9 1999-08-03 11:43:06obachman Exp $1 // $Id: homolog.lib,v 1.10 1999-12-13 15:33:47 obachman Exp $ 2 2 //(BM/GMG) 3 3 /////////////////////////////////////////////////////////////////////////////// 4 4 5 version="$Id: homolog.lib,v 1. 9 1999-08-03 11:43:06obachman Exp $";5 version="$Id: homolog.lib,v 1.10 1999-12-13 15:33:47 obachman Exp $"; 6 6 info=" 7 7 LIBRARY: homolog.lib PROCEDURES FOR HOMOLOGICAL ALGEBRA … … 554 554 0<--M'<-- F0 <-M-- F1 <-- F2 <--... resp. 0<--N'<-- G0 <--N- G1 be 555 555 a free resolution of M' resp. a presentations of N'. Consider 556 @format 556 557 0 0 0 557 558 |^ |^ |^ … … 562 563 |C |B 563 564 Hom(Fk,G1) -----> Hom(Fk+1,G1) 565 @end format 564 566 (Ak,Ak+1 induced by M and B,C induced by N). 565 567 Let K=modulo(Ak+1,B), J=module(Ak)+module(C) and Ext=modulo(K,J), … … 568 570 R^q -Ext-> R^p --K->Hom(Fk,G0)/im(Ak)+im(C) --Ak+1->Hom(Fk+1,G0)/im(B) 569 571 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 572 RETURN: 573 Ext, of type module, a presentation of Ext^k(M',N') if v is of type 571 574 int, resp. a list of Ext^k (k=v[1],v[2],...) if v is of type intvec. 572 575 In case of a third argument of any type return a list: … … 715 718 Let ...-->F1 --M-> F0-->M'-->0 and ...-->G1 --N-> G0-->N'-->0 be 716 719 presentations of M' and N'. Consider 720 @format 717 721 0 0 718 722 |^ |^ … … 728 732 R^q -Hom-> R^p --D-> Hom(F0,G0)/im(C) --A-> Hom(F1,G0)/im(B). 729 733 Hence Hom presents Hom(M',N') 734 @end format 730 735 RETURN: Hom, of type module, presentation of Hom(M',N') or, 731 736 in case of 3 arguments, a list: … … 845 850 (R=basering) and let A:R^m-->R^n a matrix inducing a map A':M'-->N'. 846 851 Compute a presentation K of ker(A') as in the commutative diagram: 852 @format 847 853 ker(A') ---> M' --A'--> N' 848 854 |^ |^ |^ … … 853 859 | | | 854 860 R^s ---> R^p -----> R^q 861 @end format 855 862 RETURN: module K, a presentation of ker(A') 856 863 EXAMPLE: example kernel; shows examples
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