Changeset 50cbdc in git for Singular/LIB/brnoeth.lib
- Timestamp:
- Aug 27, 2001, 4:48:02 PM (23 years ago)
- Branches:
- (u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')
- Children:
- 2567b5a6cb7109be5a83e53eb94abb1c38fb9945
- Parents:
- 3de58c9ca0aeaafdf5cb29f986967bffa405b542
- File:
-
- 1 edited
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Singular/LIB/brnoeth.lib
r3de58c r50cbdc 1 version="$Id: brnoeth.lib,v 1.11 2001-02-09 13:11:35 lossen Exp $"; 1 version="$Id: brnoeth.lib,v 1.12 2001-08-27 14:47:46 Singular Exp $"; 2 category="Miscellaneous"; 2 3 info=" 3 4 LIBRARY: brnoeth.lib Brill-Noether Algorithm, Weierstrass-SG and AG-codes … … 1981 1982 In the intvec L[4] (conductor) the i-th entry corresponds to the 1982 1983 i-th entry in the list of places L[3]. 1983 1984 1984 1985 With no optional arguments, the conductor is computed by 1985 1986 local invariants of the singularities; otherwise it is computed … … 1989 1990 of the places above P in the list of closed places L[3]. @* 1990 1991 If the point is at infinity, P[1] is a homogeneous irreducible 1991 polynomial in two variables. 1992 1993 If @code{printlevel>=0} additional comments are displayed (default: 1994 @code{printlevel=0}). 1992 polynomial in two variables. 1993 1994 If @code{printlevel>=0} additional comments are displayed (default: 1995 @code{printlevel=0}). 1995 1996 KEYWORDS: Hamburger-Noether expansions; adjunction divisor 1996 1997 SEE ALSO: closed_points, NSplaces … … 2126 2127 Aff_SLocus; // ideal of the affine singular locus 2127 2128 Aff_SPoints[1]; // 1st affine singular point: (1:1:1), no.1 2128 Inf_Points[1]; // singular point(s) at infinity: (1:0:0), no.4 2129 Inf_Points[1]; // singular point(s) at infinity: (1:0:0), no.4 2129 2130 Inf_Points[2]; // list of non-singular points at infinity 2130 2131 // … … 2139 2140 // 2140 2141 pause("press RETURN"); 2141 // we look at the place(s) of degree 2 by changing to the ring 2142 // we look at the place(s) of degree 2 by changing to the ring 2142 2143 C[5][2][1]; 2143 def S(2)=C[5][2][1]; 2144 def S(2)=C[5][2][1]; 2144 2145 setring S(2); 2145 2146 POINTS; // base point(s) of place(s) of degree 2: (1:a:1) … … 2164 2165 See @ref{Adj_div} for a description of the entries in L. 2165 2166 NOTE: The list_expression should be the output of the procedure Adj_div.@* 2166 If @code{printlevel>=0} additional comments are displayed (default: 2167 @code{printlevel=0}). 2167 If @code{printlevel>=0} additional comments are displayed (default: 2168 @code{printlevel=0}). 2168 2169 SEE ALSO: closed_points, Adj_div 2169 2170 EXAMPLE: example NSplaces; shows an example … … 3369 3370 list C=Adj_div(x3y+y3+x); 3370 3371 C=NSplaces(3,C); 3371 // the first 3 Places in C[3] are of degree 1. 3372 // the first 3 Places in C[3] are of degree 1. 3372 3373 // we define the rational divisor G = 4*C[3][1]+4*C[3][3] (of degree 8): 3373 3374 intvec G=4,0,4; … … 3401 3402 // programm 3402 3403 poly auxp=gcd(F[1],F[2]); 3403 return(ideal(division( auxp,F)[1]));3404 return(ideal(division(F,auxp)[1])); 3404 3405 } 3405 3406 /////////////////////////////////////////////////////////////////////////////// … … 3522 3523 NOTE: The procedure must be called from the ring CURVE[1][2], 3523 3524 where CURVE is the output of the procedure @code{NSplaces}. 3524 @* i represents the place CURVE[3][i]. 3525 @* i represents the place CURVE[3][i]. 3525 3526 @* Rational functions are represented by numerator/denominator 3526 3527 in form of ideals with two homogeneous generators. … … 3915 3916 def ER=HC[1][4]; 3916 3917 setring ER; 3917 intvec G=5; // the rational divisor G = 5*HC[3][1] 3918 intvec G=5; // the rational divisor G = 5*HC[3][1] 3918 3919 intvec D=2..9; // D = sum of the rational places no. 2..9 over F_4 3919 3920 // let us construct the corresponding evaluation AG code : … … 3962 3963 def ER=HC[1][4]; 3963 3964 setring ER; 3964 intvec G=5; // the rational divisor G = 5*HC[3][1] 3965 intvec G=5; // the rational divisor G = 5*HC[3][1] 3965 3966 intvec D=2..9; // D = sum of the rational places no. 2..9 over F_4 3966 3967 // let us construct the corresponding residual AG code : … … 4366 4367 def ER=HC[1][4]; 4367 4368 setring ER; 4368 intvec G=5; // the rational divisor G = 5*HC[3][1] 4369 intvec G=5; // the rational divisor G = 5*HC[3][1] 4369 4370 intvec D=2..9; // D = sum of the rational places no. 2..9 over F_4 4370 4371 // construct the corresp. residual AG code of type [8,3,>=5] over F_4: 4371 4372 matrix C=AGcode_Omega(G,D,HC); 4372 // we can correct 1 error and the genus is 1, thus F must have degree 2 4373 // we can correct 1 error and the genus is 1, thus F must have degree 2 4373 4374 // and support disjoint from that of D; 4374 4375 intvec F=2; … … 4516 4517 def ER=HC[1][4]; 4517 4518 setring ER; 4518 intvec G=5; // the rational divisor G = 5*HC[3][1] 4519 intvec G=5; // the rational divisor G = 5*HC[3][1] 4519 4520 intvec D=2..9; // D = sum of the rational places no. 2..9 over F_4 4520 4521 // construct the corresp. residual AG code of type [8,3,>=5] over F_4:
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