bash-2.05a$ mwrank3 Program mwrank: uses 2-descent (via 2-isogeny if possible) to determine the rank of an elliptic curve E over Q, and list a set of points which generate E(Q) modulo 2E(Q). and finally search for further points on the curve. For more details see the file mwrank.doc. For details of algorithms see the author's book. Please acknowledge use of this program in published work, and send problems to John.Cremona@nottingham.ac.uk. Version compiled on Feb 11 2003 at 17:40:15 by GCC 3.2.1 using base arithmetic option LiDIA_ALL (LiDIA bigints and multiprecision floating point) Using LiDIA multiprecision floating point with 15 decimal places. Enter curve: [0,0,0,-9,81] Curve [0,0,0,-9,81] : No points of order 2 Basic pair: I=27, J=-2187 disc=-4704237 2-adic index bound = 2 2-adic index = 2 Two (I,J) pairs Looking for quartics with I = 27, J = -2187 Looking for Type 3 quartics: Trying positive a from 1 up to 3 (square a first...) (1,-1,0,9,0) --trivial (1,-1,6,5,-2) --nontrivial...(x:y:z) = (1 : 1 : 0) Point = [-30 : 63 : 8] height = 2.33771265006877 Rank of B=im(eps) increases to 1 (1,2,-9,9,0) --trivial (1,2,9,9,0) --trivial Trying positive a from 1 up to 3 (...then non-square a) (3,1,3,6,1) --trivial Trying negative a from -1 down to -2 Finished looking for Type 3 quartics. Looking for quartics with I = 432, J = -139968 Looking for Type 3 quartics: Trying positive a from 1 up to 15 (square a first...) (1,0,-54,216,-207) --nontrivial...(x:y:z) = (1 : 1 : 0) Point = [9 : 27 : 1] height = 0.912532500970101 Doubling global 2-adic index to 2 global 2-adic index is equal to local index so we abort the search for large quartics Rank of B=im(eps) increases to 2 Exiting search for large quartics after finding enough globally soluble ones. Mordell rank contribution from B=im(eps) = 2 Selmer rank contribution from B=im(eps) = 2 Sha rank contribution from B=im(eps) = 0 Mordell rank contribution from A=ker(eps) = 0 Selmer rank contribution from A=ker(eps) = 0 Sha rank contribution from A=ker(eps) = 0 Rank = 2 Points generating E(Q)/2E(Q): Point [9 : 27 : 1], height = 0.912532500970101 Point [-30 : 63 : 8], height = 2.33771265006877 After descent, rank of points found is 2 Generator 1 is [9 : 27 : 1]; height 0.912532500970101 Generator 2 is [-30 : 63 : 8]; height 2.33771265006877 The rank has been determined unconditionally. The basis given is for a subgroup of full rank of the Mordell-Weil group (modulo torsion), possibly of index greater than 1. Regulator (of this subgroup) = 0.18794827330682 (3.2 seconds) Enter curve: [0,0,0,0,0] bash-2.05a$