/* This code can be loaded, or copied and pasted, into Magma. It will load the data associated to the HMF, including the field, level, and Hecke and Atkin-Lehner eigenvalue data. At the *bottom* of the file, there is code to recreate the Hilbert modular form in Magma, by creating the HMF space and cutting out the corresponding Hecke irreducible subspace. From there, you can ask for more eigenvalues or modify as desired. It is commented out, as this computation may be lengthy. */ P := PolynomialRing(Rationals()); g := P![7, 6, -5, -2, 1]; F := NumberField(g); ZF := Integers(F); NN := ideal; primesArray := [ [4, 2, -w^2 + w + 3], [7, 7, w], [7, 7, -w^2 + 2*w + 1], [7, 7, w^2 - 2], [7, 7, w - 1], [23, 23, -w^3 + w^2 + 3*w - 1], [23, 23, w^3 - 2*w^2 - 2*w + 2], [31, 31, w^2 - 5], [31, 31, -w^2 + 2*w + 4], [41, 41, -w^3 + 2*w^2 + 2*w - 6], [41, 41, w^3 - w^2 - 3*w - 3], [47, 47, w^2 - 2*w - 5], [47, 47, w^2 - 6], [71, 71, -w^3 + 2*w^2 + 3*w - 1], [71, 71, -w^3 + w^2 + 4*w - 3], [79, 79, -w - 3], [79, 79, w - 4], [81, 3, -3], [89, 89, w^2 - 3*w - 2], [89, 89, w^2 + w - 4], [97, 97, 2*w^3 - 5*w^2 - 4*w + 9], [97, 97, -2*w^3 + w^2 + 8*w + 2], [113, 113, w^3 - 2*w^2 - 4*w + 2], [113, 113, w^3 - w^2 - 5*w + 3], [121, 11, 2*w^2 - w - 9], [121, 11, -2*w^2 + 3*w + 8], [127, 127, w^3 - 3*w^2 - 2*w + 5], [127, 127, w^3 - 5*w - 1], [137, 137, 2*w - 1], [167, 167, 2*w^3 - 2*w^2 - 7*w - 2], [167, 167, w^3 - 7*w - 4], [167, 167, 2*w^3 - w^2 - 9*w - 2], [167, 167, 2*w^3 - 4*w^2 - 5*w + 9], [191, 191, 2*w^3 - 4*w^2 - 5*w + 5], [191, 191, -2*w^3 + 2*w^2 + 7*w - 2], [193, 193, -2*w^3 + 3*w^2 + 6*w - 6], [193, 193, -2*w^3 + 2*w^2 + 7*w - 4], [193, 193, -2*w^3 + 4*w^2 + 5*w - 3], [193, 193, 2*w^3 - 3*w^2 - 6*w + 1], [199, 199, -w^3 - 2*w^2 + 6*w + 10], [199, 199, -w^3 + 5*w^2 - w - 13], [223, 223, -w^3 + 2*w^2 + 3*w - 8], [223, 223, w^3 - w^2 - 4*w - 4], [233, 233, -w^2 - 1], [233, 233, w^2 - 2*w + 2], [239, 239, 3*w^2 - 2*w - 13], [239, 239, 3*w^2 - 4*w - 12], [241, 241, w^3 - w^2 - 6*w + 3], [241, 241, w^3 - 2*w^2 - 5*w + 3], [257, 257, -w^3 + 3*w^2 + 4*w - 9], [257, 257, -2*w^3 + 4*w^2 + 8*w - 11], [257, 257, -w^3 + 2*w^2 + 4], [257, 257, w^3 - 7*w - 3], [263, 263, -w^3 + w^2 + 3*w + 5], [263, 263, w^3 - 5*w^2 + 12], [263, 263, -w^3 - 2*w^2 + 7*w + 8], [263, 263, -w^3 + 7*w + 2], [271, 271, -w^3 + 3*w^2 + 2*w - 3], [271, 271, w^3 - 5*w + 1], [289, 17, 3*w^2 - 3*w - 8], [289, 17, 3*w^2 - 3*w - 10], [311, 311, -2*w^3 + 2*w^2 + 7*w - 1], [311, 311, -w^3 + 5*w^2 - w - 11], [311, 311, w^3 + 2*w^2 - 6*w - 8], [311, 311, -2*w^3 + 4*w^2 + 5*w - 6], [337, 337, w^3 - w^2 - 2*w - 4], [337, 337, 2*w^3 - 9*w - 4], [337, 337, 2*w^3 - 6*w^2 - 3*w + 11], [337, 337, -w^3 + 2*w^2 + w - 6], [353, 353, -w^3 + 4*w^2 - 12], [353, 353, w^3 + w^2 - 5*w - 9], [359, 359, 2*w^3 - 4*w^2 - 6*w + 5], [359, 359, 2*w^3 - 2*w^2 - 8*w + 3], [361, 19, -w^3 + 5*w^2 - 13], [361, 19, w^3 + 2*w^2 - 7*w - 9], [367, 367, 2*w^3 - 10*w - 5], [367, 367, w^3 - w^2 - 6*w + 2], [367, 367, -w^3 + 2*w^2 + 5*w - 4], [367, 367, 2*w^3 - 6*w^2 - 4*w + 13], [401, 401, -w^3 + 2*w^2 + 5*w - 5], [401, 401, -w^3 + w^2 + 6*w - 1], [409, 409, 2*w^3 - 3*w^2 - 6*w + 4], [409, 409, 3*w^3 - 3*w^2 - 12*w + 1], [409, 409, -3*w^3 + 6*w^2 + 9*w - 11], [409, 409, -2*w^3 + 3*w^2 + 6*w - 3], [431, 431, 3*w^2 - 5*w - 10], [431, 431, w^3 + w^2 - 8*w - 3], [457, 457, -2*w^3 + 4*w^2 + 4*w - 5], [457, 457, -2*w^3 + 2*w^2 + 6*w - 1], [463, 463, -2*w^3 + 7*w^2 + w - 16], [463, 463, 3*w^3 - 6*w^2 - 8*w + 8], [503, 503, -w^3 + 3*w^2 + 2*w - 12], [503, 503, -w^3 + 4*w^2 + 4*w - 10], [521, 521, w^3 + w^2 - 6*w - 2], [521, 521, -w^3 + 4*w^2 + w - 6], [529, 23, w^2 - w - 8], [569, 569, w^3 - 3*w - 6], [569, 569, -w^3 + 3*w^2 - 8], [577, 577, -w^3 + 4*w^2 - w - 10], [577, 577, w^3 + w^2 - 4*w - 8], [593, 593, -w^3 + 3*w^2 - 12], [593, 593, w^3 - 3*w - 10], [599, 599, w^3 + 3*w^2 - 7*w - 9], [599, 599, -w^3 + 3*w^2 + 3*w - 13], [601, 601, w^2 + 2*w - 4], [601, 601, w^2 - 4*w - 1], [607, 607, 2*w^2 - 13], [607, 607, w^3 + 2*w^2 - 7*w - 5], [607, 607, 2*w^3 - 3*w^2 - 8*w + 8], [607, 607, 2*w^2 - 4*w - 11], [617, 617, w^3 + w^2 - 9*w - 1], [617, 617, w^3 - w^2 - 4*w - 5], [617, 617, -w^3 + 2*w^2 + 3*w - 9], [617, 617, -w^3 + 4*w^2 + 4*w - 8], [625, 5, -5], [631, 631, -w^3 + 5*w^2 - 2*w - 13], [631, 631, w^3 + 2*w^2 - 5*w - 11], [641, 641, w^2 - 2*w + 3], [641, 641, -w^3 + 6*w - 2], [641, 641, -w^3 + 3*w^2 + 3*w - 3], [641, 641, -w^2 - 2], [647, 647, -2*w^3 + 5*w^2 + 4*w - 6], [647, 647, 2*w^3 - 4*w^2 - 5*w - 1], [647, 647, 3*w^3 - 7*w^2 - 7*w + 13], [647, 647, -2*w^3 + w^2 + 8*w - 1], [673, 673, -w^3 + 7*w - 2], [673, 673, -w^3 + 3*w^2 + 4*w - 4], [719, 719, -2*w^3 + 5*w^2 + 3*w - 12], [719, 719, 4*w^2 - 5*w - 10], [719, 719, -4*w^2 + 3*w + 11], [719, 719, 2*w^3 - w^2 - 7*w - 6], [727, 727, -w - 5], [727, 727, w - 6], [743, 743, w^2 + 2*w - 11], [743, 743, w^3 + 4*w^2 - 11*w - 11], [751, 751, -2*w^2 + w + 13], [751, 751, 2*w^2 - 3*w - 12], [769, 769, 2*w^3 - 6*w^2 - 3*w + 17], [769, 769, 3*w^3 - 2*w^2 - 11*w + 2], [809, 809, w^3 + 3*w^2 - 6*w - 11], [809, 809, -3*w^3 + 5*w^2 + 8*w - 11], [823, 823, -w^3 + w^2 + 2*w - 6], [823, 823, 4*w^2 - 5*w - 11], [823, 823, -4*w^2 + 3*w + 12], [823, 823, -w^3 + 4*w^2 + 4*w - 12], [839, 839, -2*w^3 + w^2 + 6*w + 5], [839, 839, -3*w^3 + 8*w^2 + 7*w - 17], [839, 839, 3*w^3 - w^2 - 14*w - 5], [839, 839, -2*w^3 + 5*w^2 + 2*w - 10], [857, 857, w^3 + w^2 - 8*w - 2], [857, 857, -w^3 + 4*w^2 + 3*w - 8], [863, 863, -w^3 + w^2 - w - 1], [863, 863, w^3 - 2*w^2 + 2*w - 2], [911, 911, -w^3 + 3*w^2 - 11], [911, 911, w^3 - 3*w - 9], [919, 919, -2*w^3 + w^2 + 8*w - 2], [919, 919, -2*w^3 + 5*w^2 + 4*w - 5], [929, 929, -2*w^3 + 2*w^2 + 9*w - 4], [929, 929, 2*w^3 - 9*w - 12], [929, 929, 2*w^3 - 6*w^2 - 3*w + 19], [929, 929, -2*w^3 + 4*w^2 + 7*w - 5], [937, 937, -w^3 + 2*w^2 - 6], [937, 937, -w^3 + 3*w^2 - 10], [937, 937, w^3 - 3*w - 8], [937, 937, w^3 - w^2 - w - 5], [953, 953, 2*w^3 - 6*w^2 - 3*w + 18], [953, 953, -3*w^3 + 3*w^2 + 11*w - 5], [961, 31, 4*w^2 - 4*w - 11], [967, 967, -w^3 + 7*w - 3], [967, 967, -2*w^3 + 2*w^2 + 11*w + 2], [967, 967, -w^3 - 4*w^2 + 9*w + 9], [967, 967, -w^3 + 3*w^2 + 4*w - 3], [977, 977, 2*w^2 - 5*w - 8], [977, 977, -w^3 + 2*w^2 - w + 6], [977, 977, -w^3 + w^2 - 6], [977, 977, 2*w^2 + w - 11], [983, 983, -w^3 + 6*w^2 - 2*w - 16], [983, 983, w^3 + 3*w^2 - 7*w - 13]]; primes := [ideal : I in primesArray]; heckePol := x^4 - 4*x^3 - 13*x^2 + 34*x + 71; K := NumberField(heckePol); heckeEigenvaluesArray := [-1, e, -1, e^3 - 5/2*e^2 - 15/2*e + 7/2, -1/2*e^2 + 1/2*e + 13/2, -1/2*e^3 - e^2 + 9*e + 35/2, 1/2*e^3 + 3/2*e^2 - 19/2*e - 21, 9/2*e^2 - 19/2*e - 75/2, -e^3 + 3/2*e^2 + 17/2*e + 15/2, -e^2 + e + 9, e^3 - 3*e^2 - 6*e + 14, -1/2*e^3 + 13/2*e^2 - 17/2*e - 45, -1/2*e^3 + 2*e^2 + 3*e - 3/2, -2*e^3 + 3*e^2 + 19*e + 11, e^3 - 7*e^2 + 3*e + 44, -1/2*e^3 + 23/2*e^2 - 35/2*e - 89, e^3 - 7*e^2 + 2*e + 39, -1/2*e^3 + e^2 + 3*e - 9/2, -1/2*e^3 + e^2 + 4*e + 15/2, 3*e^3 - 12*e^2 - 13*e + 52, e^3 - 13/2*e^2 - 3/2*e + 83/2, 1/2*e^3 - 7/2*e^2 - 1/2*e + 30, e^3 - 8*e^2 + 4*e + 53, -e^3 + 5*e^2 + 2*e - 25, e^3 - 4*e^2 - 7*e + 27, 27/2*e^2 - 51/2*e - 231/2, -23/2*e^2 + 45/2*e + 197/2, e^3 - 8*e^2 + 5*e + 47, 3/2*e^3 - 11*e^2 + 7*e + 139/2, 1/2*e^3 - 10*e^2 + 15*e + 147/2, e^3 - 17*e^2 + 19*e + 126, 2*e^3 - 6*e^2 - 16*e + 26, -2*e^3 + 7*e^2 + 15*e - 29, -10*e^2 + 21*e + 85, -9/2*e^3 + 19*e^2 + 18*e - 165/2, -6*e^3 + 15*e^2 + 47*e - 33, -9/2*e^3 + 15*e^2 + 28*e - 109/2, e^3 - 12*e^2 + 12*e + 81, 2*e^3 - 2*e^2 - 24*e - 18, -2*e^3 + 10*e^2 + 10*e - 56, 4*e^3 - 15/2*e^2 - 71/2*e - 15/2, -3*e^3 - 5/2*e^2 + 93/2*e + 123/2, -1/2*e^3 - 7*e^2 + 18*e + 131/2, e^3 - e^2 - 13*e + 2, -3*e^3 - e^2 + 39*e + 56, 2*e^3 + 6*e^2 - 38*e - 82, 3*e^3 - 13/2*e^2 - 61/2*e + 21/2, -5/2*e^3 + 4*e^2 + 24*e + 25/2, -5*e^3 + 23/2*e^2 + 79/2*e - 31/2, -3/2*e^3 + 9*e^2 - 2*e - 111/2, 2*e^3 - 3*e^2 - 15*e - 25, -3*e^3 + 19*e^2 + 5*e - 104, -e^3 + 19/2*e^2 - 17/2*e - 111/2, -5/2*e^3 + 15*e^2 + 3*e - 149/2, -16*e^2 + 29*e + 137, 9/2*e^3 - 35/2*e^2 - 45/2*e + 75, 2*e^3 + 7/2*e^2 - 67/2*e - 111/2, 3*e^3 - 3*e^2 - 30*e - 32, 1/2*e^3 + 14*e^2 - 30*e - 269/2, 4*e^3 + 1/2*e^2 - 99/2*e - 167/2, 4*e^3 - 45/2*e^2 - 11/2*e + 245/2, 1/2*e^3 + 17*e^2 - 37*e - 315/2, -2*e^3 + 13*e^2 - 3*e - 77, -e^3 - 33/2*e^2 + 89/2*e + 315/2, -11/2*e^3 + 23*e^2 + 22*e - 211/2, -9/2*e^3 + 17*e^2 + 18*e - 129/2, 3*e^3 + 3/2*e^2 - 87/2*e - 133/2, -9/2*e^3 + 23*e^2 + 9*e - 237/2, -3*e^3 + 8*e^2 + 22*e - 11, 2*e^3 + 5*e^2 - 31*e - 87, 3/2*e^2 - 3/2*e + 9/2, -3*e^3 + e^2 + 35*e + 44, -e^3 + 39/2*e^2 - 59/2*e - 289/2, -7/2*e^3 + 8*e^2 + 33*e - 17/2, 3*e^3 - 9*e^2 - 19*e + 40, 11/2*e^3 - 11*e^2 - 48*e + 31/2, 3*e^3 - 16*e^2 - 4*e + 85, -3*e^3 + 3*e^2 + 27*e + 32, -e^2 + e + 3, 1/2*e^3 + 13/2*e^2 - 53/2*e - 52, -5/2*e^3 + e^2 + 31*e + 75/2, e^3 - 23/2*e^2 + 31/2*e + 149/2, 7/2*e^3 - 6*e^2 - 31*e - 31/2, -3*e^3 + 63/2*e^2 - 49/2*e - 435/2, 5*e^3 - 61/2*e^2 - 11/2*e + 339/2, -5*e^3 + 3*e^2 + 59*e + 56, -9/2*e^3 + 23*e^2 + 15*e - 237/2, e^3 - 23/2*e^2 + 15/2*e + 165/2, -8*e^2 + 16*e + 58, -1/2*e^3 + 6*e^2 - 107/2, -4*e^3 + 23*e^2 + 5*e - 135, 2*e^3 - 20*e^2 + 19*e + 142, -e^3 + 13*e^2 - 15*e - 96, 5/2*e^3 - 5/2*e^2 - 47/2*e - 11, 3*e^3 + 5*e^2 - 55*e - 72, 3*e^3 - 34*e - 73, 2*e^3 - 7*e^2 - 19*e + 39, -7/2*e^3 + 39/2*e^2 + 25/2*e - 105, e^3 + 7/2*e^2 - 49/2*e - 91/2, -9/2*e^3 + 13*e^2 + 31*e - 65/2, 3/2*e^3 - 15/2*e^2 - 9/2*e + 28, 2*e^3 - 39*e^2 + 55*e + 301, -3*e^3 - e^2 + 35*e + 70, -2*e^3 - 2*e^2 + 38*e + 28, 4*e^3 - 83/2*e^2 + 61/2*e + 561/2, -2*e^3 + 3*e^2 + 21*e + 9, -1/2*e^3 + 13*e^2 - 17*e - 169/2, -e^3 + 11/2*e^2 + 11/2*e - 111/2, -e^3 + 6*e^2 + 4*e - 9, -5/2*e^3 - 1/2*e^2 + 73/2*e + 54, 4*e^2 - 10*e - 16, -9/2*e^3 + 23*e^2 + 15*e - 229/2, -15/2*e^3 + 59/2*e^2 + 73/2*e - 136, -4*e^3 - 21/2*e^2 + 137/2*e + 325/2, -e^3 + 8*e + 5, 5/2*e^3 - 4*e^2 - 22*e - 53/2, 3/2*e^3 - 8*e^2 + 2*e + 101/2, -4*e^3 + 33/2*e^2 + 29/2*e - 167/2, 3*e^3 - e^2 - 39*e - 36, -3/2*e^3 - 4*e^2 + 33*e + 71/2, e^3 - 2*e^2 - 11*e - 16, e^3 + 7*e^2 - 27*e - 78, -3*e^3 + 5/2*e^2 + 65/2*e + 67/2, -4*e^3 + 13/2*e^2 + 65/2*e + 73/2, e^3 - 37/2*e^2 + 41/2*e + 319/2, -4*e^3 + 25/2*e^2 + 51/2*e - 65/2, -2*e^3 + 39/2*e^2 - 19/2*e - 271/2, -e^3 - 35/2*e^2 + 83/2*e + 357/2, 1/2*e^3 - 21*e^2 + 36*e + 309/2, 3*e^3 - 1/2*e^2 - 85/2*e - 39/2, 6*e^3 - 85/2*e^2 + 17/2*e + 509/2, 5*e^3 - 27*e^2 - 10*e + 147, 7/2*e^3 - 45/2*e^2 + 9/2*e + 156, e^3 - 7/2*e^2 - 5/2*e + 37/2, 13/2*e^3 - 5*e^2 - 75*e - 99/2, 9/2*e^3 - 21/2*e^2 - 91/2*e + 24, 4*e^3 + 3*e^2 - 59*e - 75, 2*e^3 - 12*e^2 + 4*e + 76, 4*e^3 - 17*e^2 - 11*e + 99, -5*e^3 + 12*e^2 + 33*e + 9, -4*e^3 + 22*e^2 + 6*e - 112, 2*e^3 - 22*e^2 + 12*e + 166, -17/2*e^3 + 53/2*e^2 + 103/2*e - 84, -5/2*e^3 - 5/2*e^2 + 53/2*e + 84, 7/2*e^2 - 37/2*e - 21/2, -2*e^3 + 7*e^2 + 13*e - 21, 5/2*e^3 - 8*e^2 - 19*e + 95/2, 8*e^3 - 24*e^2 - 56*e + 70, -3*e^3 + 14*e^2 + 16*e - 57, 15/2*e^3 - 5*e^2 - 94*e - 117/2, 15/2*e^3 - 53/2*e^2 - 99/2*e + 108, 6*e^3 - 15*e^2 - 51*e + 37, 5*e^3 - 43/2*e^2 - 55/2*e + 187/2, -11/2*e^3 + 49/2*e^2 + 35/2*e - 108, -25/2*e^2 + 47/2*e + 255/2, -3*e^3 - 4*e^2 + 50*e + 41, 4*e^3 - 19*e^2 - 9*e + 123, -5*e^3 + 2*e^2 + 54*e + 63, -3*e^3 - 27/2*e^2 + 149/2*e + 303/2, -3*e^3 + 25/2*e^2 + 37/2*e - 117/2, 3*e^3 + 11/2*e^2 - 89/2*e - 287/2, 7/2*e^3 - 8*e^2 - 36*e + 21/2, 2*e^3 - 27*e^2 + 31*e + 179, -7*e^3 + 67/2*e^2 + 51/2*e - 271/2, -7*e^3 + 35/2*e^2 + 103/2*e - 91/2, -9/2*e^3 + 20*e^2 + 27*e - 199/2, 2*e^3 - 35/2*e^2 + 27/2*e + 167/2, 1/2*e^3 + e^2 - 4*e - 67/2, 2*e^3 - 49/2*e^2 + 61/2*e + 389/2, -11/2*e^3 + 24*e^2 + 20*e - 229/2, -7/2*e^3 - 43/2*e^2 + 175/2*e + 243, 3*e^3 + 19*e^2 - 77*e - 204, 4*e^3 - 25*e^2 - 11*e + 149, -6*e^3 + 39/2*e^2 + 65/2*e - 119/2, -6*e^3 + 22*e^2 + 35*e - 92, -7*e^3 + 21*e^2 + 45*e - 48, -17/2*e^3 + 8*e^2 + 88*e + 161/2, -13/2*e^3 + 49/2*e^2 + 75/2*e - 97]; heckeEigenvalues := AssociativeArray(); for i := 1 to #heckeEigenvaluesArray do heckeEigenvalues[primes[i]] := heckeEigenvaluesArray[i]; end for; ALEigenvalues := AssociativeArray(); ALEigenvalues[ideal] := 1; ALEigenvalues[ideal] := 1; // EXAMPLE: // pp := Factorization(2*ZF)[1][1]; // heckeEigenvalues[pp]; print "To reconstruct the Hilbert newform f, type f, iso := Explode(make_newform());"; function make_newform(); M := HilbertCuspForms(F, NN); S := NewSubspace(M); // SetVerbose("ModFrmHil", 1); NFD := NewformDecomposition(S); newforms := [* Eigenform(U) : U in NFD *]; if #newforms eq 0 then; print "No Hilbert newforms at this level"; return 0; end if; print "Testing ", #newforms, " possible newforms"; newforms := [* f: f in newforms | IsIsomorphic(BaseField(f), K) *]; print #newforms, " newforms have the correct Hecke field"; if #newforms eq 0 then; print "No Hilbert newform found with the correct Hecke field"; return 0; end if; autos := Automorphisms(K); xnewforms := [* *]; for f in newforms do; if K eq RationalField() then; Append(~xnewforms, [* f, autos[1] *]); else; flag, iso := IsIsomorphic(K,BaseField(f)); for a in autos do; Append(~xnewforms, [* f, a*iso *]); end for; end if; end for; newforms := xnewforms; for P in primes do; xnewforms := [* *]; for f_iso in newforms do; f, iso := Explode(f_iso); if HeckeEigenvalue(f,P) eq iso(heckeEigenvalues[P]) then; Append(~xnewforms, f_iso); end if; end for; newforms := xnewforms; if #newforms eq 0 then; print "No Hilbert newform found which matches the Hecke eigenvalues"; return 0; else if #newforms eq 1 then; print "success: unique match"; return newforms[1]; end if; end if; end for; print #newforms, "Hilbert newforms found which match the Hecke eigenvalues"; return newforms[1]; end function;