/* 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![2, -1, -6, -1, 1]; F := NumberField(g); ZF := Integers(F); NN := ideal; primesArray := [ [2, 2, w], [5, 5, w - 1], [8, 2, -w^3 + w^2 + 6*w + 1], [9, 3, -w^3 + w^2 + 5*w + 1], [9, 3, -w^3 + 2*w^2 + 3*w - 1], [19, 19, -w^3 + 2*w^2 + 4*w - 1], [23, 23, w^2 - 2*w - 1], [29, 29, w^2 - 3*w - 1], [29, 29, -w^2 + w + 3], [37, 37, w^3 - w^2 - 5*w + 1], [43, 43, -w^3 + 2*w^2 + 3*w - 3], [47, 47, -w^2 + 2*w + 5], [47, 47, 2*w^3 - 2*w^2 - 11*w - 5], [53, 53, -w^3 + 2*w^2 + 2*w + 1], [59, 59, -w - 3], [73, 73, w^2 - w + 1], [73, 73, 2*w^3 - 2*w^2 - 12*w - 5], [79, 79, 4*w^3 - 4*w^2 - 22*w - 7], [97, 97, 2*w^3 - 3*w^2 - 9*w + 1], [101, 101, 2*w^2 - 2*w - 9], [103, 103, -w^3 + 2*w^2 + 3*w - 5], [107, 107, 2*w^3 - 4*w^2 - 6*w + 1], [113, 113, 2*w^2 - 4*w - 7], [113, 113, w^3 - w^2 - 7*w + 1], [125, 5, -2*w^3 + 5*w^2 + 7*w - 11], [137, 137, -w^2 + 4*w + 3], [137, 137, -w^3 + 3*w^2 + 3*w - 7], [139, 139, -3*w - 1], [151, 151, 2*w^3 - 2*w^2 - 11*w - 1], [157, 157, -2*w^3 + 3*w^2 + 11*w - 3], [163, 163, 2*w^3 - 3*w^2 - 8*w + 3], [163, 163, -w^3 + w^2 + 7*w + 1], [167, 167, 2*w^3 - 5*w^2 - 5*w + 1], [167, 167, -w^3 + 7*w + 3], [173, 173, -3*w^3 + 4*w^2 + 16*w - 3], [181, 181, 2*w - 3], [197, 197, -2*w^3 + 6*w^2 + 6*w - 17], [199, 199, 2*w^3 - 4*w^2 - 5*w + 1], [211, 211, w^3 - 2*w^2 - 6*w + 5], [227, 227, -w^3 + 4*w^2 + 2*w - 13], [227, 227, w^3 - 2*w^2 - 5*w - 3], [229, 229, 2*w^2 - w - 7], [233, 233, 2*w - 5], [233, 233, 3*w^3 - 4*w^2 - 16*w - 1], [239, 239, -2*w^3 + w^2 + 12*w + 11], [239, 239, -3*w^3 + 2*w^2 + 19*w + 9], [251, 251, 3*w^3 - 2*w^2 - 17*w - 7], [257, 257, -w^3 - w^2 + 7*w + 9], [257, 257, 3*w^3 - 4*w^2 - 15*w + 3], [269, 269, -3*w^3 + 4*w^2 + 14*w + 3], [271, 271, 2*w^3 - 14*w - 15], [277, 277, w^3 - 2*w^2 - w + 3], [277, 277, 2*w^3 - 6*w^2 + w + 5], [281, 281, w^3 - 2*w^2 - 3*w - 3], [281, 281, -2*w^3 + 3*w^2 + 10*w + 1], [289, 17, w^3 + 2*w^2 - 10*w - 17], [289, 17, 3*w^3 - 6*w^2 - 13*w + 13], [293, 293, 2*w^3 - w^2 - 13*w - 5], [311, 311, w^3 - w^2 - 3*w - 3], [311, 311, 2*w^3 - 3*w^2 - 11*w - 1], [313, 313, -2*w^3 + 4*w^2 + 9*w - 3], [317, 317, -3*w^3 + 3*w^2 + 17*w + 7], [331, 331, -2*w^3 + 3*w^2 + 8*w - 1], [337, 337, -4*w^3 + 6*w^2 + 19*w - 3], [347, 347, w^3 - 3*w^2 - 5*w + 1], [347, 347, -2*w^3 + 2*w^2 + 9*w - 3], [347, 347, 3*w^3 - 6*w^2 - 12*w + 11], [347, 347, w - 5], [349, 349, -w^3 + 5*w^2 - 3*w - 5], [349, 349, 2*w^3 - w^2 - 13*w - 11], [353, 353, w^3 - 2*w^2 - 4*w - 3], [353, 353, 2*w^2 - 6*w - 5], [359, 359, -2*w^3 + 3*w^2 + 6*w + 1], [367, 367, 2*w^3 - 2*w^2 - 8*w + 1], [367, 367, w^2 - 7], [373, 373, w^3 + w^2 - 7*w - 11], [373, 373, -2*w^3 + 2*w^2 + 12*w - 1], [373, 373, -2*w^3 + 15*w + 13], [373, 373, -3*w^3 + 3*w^2 + 15*w + 7], [379, 379, -2*w^3 + w^2 + 11*w + 9], [397, 397, -w^3 + 3*w^2 + 3*w - 11], [397, 397, -w^3 + 9*w - 1], [401, 401, -2*w^3 + 4*w^2 + 7*w - 7], [419, 419, -w^3 + 2*w^2 + 2*w - 5], [419, 419, -2*w^3 + 4*w^2 + 6*w + 3], [421, 421, 2*w^2 - 2*w - 7], [421, 421, 4*w^3 - 5*w^2 - 22*w - 1], [421, 421, w^2 - 3*w - 9], [421, 421, 3*w^2 - 5*w - 5], [431, 431, w^3 - 4*w^2 + 5], [431, 431, -w^3 + 6*w + 1], [433, 433, -2*w^3 + 4*w^2 + 10*w - 9], [443, 443, -w^3 + 2*w^2 + 4*w - 7], [443, 443, -3*w^3 + 6*w^2 + 10*w - 7], [479, 479, 2*w^2 - w - 9], [479, 479, 2*w^3 - 4*w^2 - 7*w - 3], [487, 487, 4*w^3 - 3*w^2 - 24*w - 9], [487, 487, -w^3 + 4*w^2 - 3*w - 3], [491, 491, -w^3 + 9*w + 3], [491, 491, -2*w^3 + 4*w^2 + 8*w - 1], [503, 503, 3*w^3 - 5*w^2 - 15*w + 3], [503, 503, w^3 - 2*w^2 - 8*w + 5], [509, 509, 2*w^3 - 2*w^2 - 8*w - 5], [509, 509, 2*w^2 - 4*w - 1], [521, 521, 3*w^3 - 4*w^2 - 15*w - 3], [541, 541, 3*w^3 - 2*w^2 - 18*w - 7], [541, 541, -2*w^3 + 5*w^2 + 6*w - 1], [547, 547, 2*w^3 - 2*w^2 - 9*w - 7], [557, 557, -2*w^2 + 4*w + 9], [563, 563, -2*w^3 + 5*w^2 + 7*w - 9], [571, 571, 3*w^3 - 7*w^2 - 7*w - 1], [571, 571, -2*w^3 + 5*w^2 + 7*w - 3], [577, 577, -3*w^3 + 4*w^2 + 16*w - 9], [587, 587, w^2 + w - 5], [593, 593, 4*w^3 - 5*w^2 - 20*w - 3], [593, 593, 3*w^2 - 5*w - 11], [601, 601, -2*w^2 + 6*w + 3], [601, 601, 3*w^3 - 6*w^2 - 11*w + 3], [607, 607, -w - 5], [613, 613, w^3 - 6*w + 1], [619, 619, -2*w^3 + 3*w^2 + 6*w - 1], [647, 647, -3*w^2 + 6*w + 5], [653, 653, 2*w^3 - w^2 - 11*w - 11], [661, 661, -2*w^3 + 3*w^2 + 6*w - 5], [661, 661, -2*w^3 + 3*w^2 + 12*w + 3], [673, 673, w^2 - 2*w + 3], [683, 683, 2*w^3 - 2*w^2 - 8*w - 1], [691, 691, 2*w^3 - 3*w^2 - 12*w + 1], [691, 691, 3*w^3 - 4*w^2 - 14*w - 1], [691, 691, -3*w^3 + 6*w^2 + 10*w + 1], [691, 691, -2*w^3 + 2*w^2 + 10*w - 3], [727, 727, -w^3 - 2*w^2 + 9*w + 15], [733, 733, 2*w^3 - 5*w^2 - 3*w + 5], [733, 733, 2*w^3 - 2*w^2 - 5*w + 1], [761, 761, -w^3 + 3*w^2 + w - 7], [769, 769, -2*w^3 + 4*w^2 + 5*w - 5], [773, 773, -2*w^3 + 2*w^2 + 13*w + 3], [787, 787, -w^3 + 4*w^2 + w - 5], [809, 809, 6*w^3 - 9*w^2 - 30*w + 5], [809, 809, 2*w^2 - 4*w - 11], [809, 809, -3*w^2 + 4*w + 13], [809, 809, w^3 - 8*w + 1], [811, 811, -5*w^3 + 11*w^2 + 11*w - 1], [823, 823, 3*w^3 - 6*w^2 - 7*w + 1], [827, 827, 3*w^3 - 20*w - 17], [829, 829, 4*w^3 - 4*w^2 - 23*w - 3], [839, 839, -w^3 + 6*w + 11], [841, 29, 4*w^3 - 4*w^2 - 22*w - 11], [853, 853, -w^2 - 3], [853, 853, 2*w^3 - w^2 - 11*w - 3], [857, 857, 2*w^3 - 2*w^2 - 12*w + 3], [863, 863, w^2 - w - 9], [877, 877, 4*w^3 - 5*w^2 - 20*w - 1], [877, 877, w^3 - w^2 - 3*w - 5], [881, 881, -w^3 + 2*w^2 + w - 5], [887, 887, -3*w^2 + 6*w + 11], [919, 919, -3*w^3 + 22*w + 19], [919, 919, 5*w^3 - 5*w^2 - 27*w - 9], [937, 937, 4*w^3 - 4*w^2 - 23*w - 9], [947, 947, w^3 + w^2 - 7*w - 13], [967, 967, 3*w^3 - 3*w^2 - 13*w + 1], [971, 971, -w^3 + 6*w^2 - 5*w - 7], [971, 971, 4*w^3 - 4*w^2 - 21*w - 5], [977, 977, -2*w^3 - 2*w^2 + 17*w + 21], [983, 983, 3*w^3 - 3*w^2 - 17*w - 1], [991, 991, -w^3 + 4*w^2 + 4*w - 5], [991, 991, -3*w^3 + 6*w^2 + 13*w - 5]]; primes := [ideal : I in primesArray]; heckePol := x^8 - 12*x^6 + 38*x^4 - 35*x^2 + 4; K := NumberField(heckePol); heckeEigenvaluesArray := [e, -1, 1/2*e^7 - 6*e^5 + 18*e^3 - 23/2*e, -1/2*e^7 + 6*e^5 - 19*e^3 + 35/2*e, -e^7 + 11*e^5 - 28*e^3 + 16*e, e^5 - 10*e^3 + 17*e, -1/2*e^7 + 6*e^5 - 19*e^3 + 39/2*e, -e^7 + 12*e^5 - 38*e^3 + 33*e, e^6 - 11*e^4 + 27*e^2 - 11, e^7 - 12*e^5 + 38*e^3 - 33*e, -e^6 + 10*e^4 - 18*e^2 - 3, -e^4 + 9*e^2 - 8, 4*e, e^4 - 7*e^2 + 8, e^4 - 7*e^2 + 6, 2*e^6 - 20*e^4 + 40*e^2 - 12, 3/2*e^7 - 18*e^5 + 57*e^3 - 97/2*e, e^7 - 10*e^5 + 18*e^3 - e, -2*e^7 + 23*e^5 - 64*e^3 + 37*e, e^6 - 10*e^4 + 16*e^2 + 7, e^4 - 9*e^2 + 12, -e^7 + 10*e^5 - 20*e^3 + 7*e, -e^6 + 10*e^4 - 18*e^2 + 7, -1/2*e^7 + 6*e^5 - 19*e^3 + 35/2*e, 2*e^6 - 21*e^4 + 45*e^2 - 20, 2*e^7 - 22*e^5 + 56*e^3 - 30*e, -e^6 + 10*e^4 - 20*e^2 + 5, -2*e^7 + 22*e^5 - 54*e^3 + 18*e, 1/2*e^7 - 7*e^5 + 29*e^3 - 65/2*e, -3/2*e^7 + 18*e^5 - 57*e^3 + 89/2*e, -e^7 + 10*e^5 - 20*e^3 + 7*e, 2*e^7 - 23*e^5 + 66*e^3 - 45*e, -e^7 + 12*e^5 - 38*e^3 + 35*e, -3/2*e^7 + 19*e^5 - 65*e^3 + 115/2*e, 1/2*e^7 - 9*e^5 + 47*e^3 - 117/2*e, -e^4 + 9*e^2 - 22, -e^6 + 12*e^4 - 38*e^2 + 29, -3/2*e^7 + 18*e^5 - 59*e^3 + 137/2*e, -2*e^6 + 21*e^4 - 45*e^2 + 10, e^6 - 10*e^4 + 22*e^2 - 9, -2*e^6 + 20*e^4 - 36*e^2 + 6, 2*e^6 - 22*e^4 + 50*e^2 - 8, 2*e^2, -2*e^7 + 20*e^5 - 38*e^3 + 2*e, e^6 - 12*e^4 + 30*e^2 + 5, -1/2*e^7 + 5*e^5 - 9*e^3 - 19/2*e, e^7 - 9*e^5 + 10*e^3 + 10*e, 2*e^6 - 21*e^4 + 49*e^2 - 16, -4*e^7 + 46*e^5 - 130*e^3 + 82*e, e^7 - 11*e^5 + 24*e^3 + 4*e, -e^4 + 11*e^2 - 2, 4*e^6 - 42*e^4 + 88*e^2 - 20, 1/2*e^7 - 6*e^5 + 19*e^3 - 35/2*e, -4*e^6 + 43*e^4 - 99*e^2 + 42, -2*e^7 + 24*e^5 - 74*e^3 + 54*e, 4*e^6 - 40*e^4 + 80*e^2 - 22, -3*e^6 + 30*e^4 - 58*e^2 + 17, -e^7 + 14*e^5 - 54*e^3 + 47*e, 2*e^6 - 22*e^4 + 58*e^2 - 30, -3*e^7 + 34*e^5 - 92*e^3 + 53*e, e^7 - 10*e^5 + 18*e^3 - 3*e, 2*e^7 - 23*e^5 + 60*e^3 - 17*e, -1/2*e^7 + 3*e^5 + 11*e^3 - 87/2*e, -1/2*e^7 + 2*e^5 + 21*e^3 - 101/2*e, 5/2*e^7 - 30*e^5 + 97*e^3 - 199/2*e, -3/2*e^7 + 16*e^5 - 37*e^3 + 9/2*e, 3*e^6 - 33*e^4 + 87*e^2 - 37, 3*e^4 - 27*e^2 + 36, e^7 - 16*e^5 + 76*e^3 - 95*e, -4*e^2 + 2, e^4 - 9*e^2 + 22, 7/2*e^7 - 38*e^5 + 95*e^3 - 113/2*e, 3*e^7 - 31*e^5 + 66*e^3 - 22*e, e^7 - 14*e^5 + 54*e^3 - 49*e, 4*e^4 - 28*e^2 + 16, -e^6 + 11*e^4 - 23*e^2 - 13, -2*e^7 + 22*e^5 - 54*e^3 + 12*e, 2*e^6 - 20*e^4 + 32*e^2 + 16, 5*e^7 - 55*e^5 + 140*e^3 - 80*e, 2*e^6 - 24*e^4 + 74*e^2 - 36, -2*e^6 + 20*e^4 - 40*e^2 + 20, 3/2*e^7 - 20*e^5 + 75*e^3 - 145/2*e, e^6 - 10*e^4 + 22*e^2 - 27, 4*e^6 - 41*e^4 + 83*e^2 - 10, -e^6 + 14*e^4 - 56*e^2 + 39, 2*e^6 - 19*e^4 + 29*e^2 + 6, 2*e^5 - 20*e^3 + 32*e, -e^6 + 13*e^4 - 41*e^2 + 19, 2*e^7 - 23*e^5 + 64*e^3 - 37*e, e^6 - 9*e^4 + 11*e^2 - 3, -e^7 + 10*e^5 - 20*e^3 + 11*e, -3*e^6 + 30*e^4 - 58*e^2 + 5, 4*e^6 - 44*e^4 + 102*e^2 - 26, e^6 - 14*e^4 + 48*e^2 - 11, -2*e^4 + 10*e^2 + 12, -e^6 + 8*e^4 + 2*e^2 - 37, -2*e^7 + 21*e^5 - 44*e^3 - 11*e, -5*e^7 + 60*e^5 - 186*e^3 + 139*e, -3/2*e^7 + 20*e^5 - 81*e^3 + 217/2*e, -1/2*e^7 + 6*e^5 - 15*e^3 - 9/2*e, 9/2*e^7 - 50*e^5 + 133*e^3 - 171/2*e, e^6 - 15*e^4 + 57*e^2 - 35, -e^6 + 11*e^4 - 23*e^2 - 5, 5*e^7 - 55*e^5 + 138*e^3 - 78*e, 13/2*e^7 - 72*e^5 + 185*e^3 - 207/2*e, -2*e^7 + 22*e^5 - 56*e^3 + 34*e, 2*e^5 - 20*e^3 + 40*e, 2*e^6 - 18*e^4 + 12*e^2 + 32, -e^6 + 12*e^4 - 40*e^2 + 27, -2*e^6 + 21*e^4 - 39*e^2 - 20, -2*e^6 + 20*e^4 - 32*e^2 - 6, e^7 - 13*e^5 + 44*e^3 - 20*e, -4*e^4 + 42*e^2 - 44, 5*e^6 - 52*e^4 + 114*e^2 - 27, 6*e^7 - 67*e^5 + 176*e^3 - 113*e, -2*e^6 + 24*e^4 - 70*e^2 + 42, -2*e^5 + 20*e^3 - 32*e, 1/2*e^7 - 7*e^5 + 27*e^3 - 57/2*e, 3*e^6 - 35*e^4 + 97*e^2 - 49, 4*e^7 - 48*e^5 + 150*e^3 - 140*e, 4*e^7 - 41*e^5 + 84*e^3 - 15*e, -1/2*e^7 + 3*e^5 + 9*e^3 - 75/2*e, -12*e^2 + 42, -2*e^6 + 21*e^4 - 47*e^2 - 10, 1/2*e^7 - 3*e^5 - 11*e^3 + 67/2*e, 4*e^6 - 43*e^4 + 103*e^2 - 22, 2*e^7 - 25*e^5 + 88*e^3 - 93*e, 6*e^7 - 69*e^5 + 192*e^3 - 117*e, 2*e^7 - 23*e^5 + 64*e^3 - 43*e, 1/2*e^7 - 6*e^5 + 15*e^3 + 41/2*e, -4*e^7 + 46*e^5 - 134*e^3 + 116*e, -2*e^6 + 20*e^4 - 42*e^2 + 16, 2*e^4 - 6*e^2 - 22, -7/2*e^7 + 37*e^5 - 83*e^3 + 83/2*e, -2*e^4 + 14*e^2 - 14, -6*e^6 + 66*e^4 - 164*e^2 + 66, e^7 - 11*e^5 + 32*e^3 - 52*e, 3*e^6 - 36*e^4 + 106*e^2 - 41, 7/2*e^7 - 42*e^5 + 133*e^3 - 245/2*e, 4*e^6 - 40*e^4 + 72*e^2 - 10, -2*e^6 + 22*e^4 - 58*e^2 + 8, 4*e^7 - 46*e^5 + 136*e^3 - 136*e, 3*e^7 - 32*e^5 + 72*e^3 - 11*e, -9/2*e^7 + 54*e^5 - 169*e^3 + 307/2*e, -2*e^6 + 18*e^4 - 12*e^2 - 40, -5*e^7 + 56*e^5 - 148*e^3 + 91*e, -2*e^6 + 19*e^4 - 31*e^2 + 14, -2*e^7 + 24*e^5 - 74*e^3 + 46*e, 6*e^6 - 57*e^4 + 89*e^2 + 24, 13/2*e^7 - 73*e^5 + 201*e^3 - 309/2*e, -2*e^7 + 24*e^5 - 76*e^3 + 56*e, 5*e^6 - 50*e^4 + 88*e^2 - 3, 1/2*e^7 - 5*e^5 + 7*e^3 - 5/2*e, 6*e^6 - 60*e^4 + 110*e^2 + 2, 2*e^6 - 24*e^4 + 70*e^2 - 46, -2*e^6 + 19*e^4 - 29*e^2 - 8, 2*e^6 - 16*e^4 + 6*e^2 + 48, 9/2*e^7 - 46*e^5 + 91*e^3 - 15/2*e, -8*e^7 + 89*e^5 - 228*e^3 + 117*e, -2*e^6 + 16*e^4 - 12*e^2 + 6, 3*e^7 - 38*e^5 + 140*e^3 - 169*e, 7*e^7 - 81*e^5 + 236*e^3 - 166*e, 5/2*e^7 - 33*e^5 + 121*e^3 - 233/2*e, 2*e^6 - 27*e^4 + 99*e^2 - 60, -6*e^7 + 65*e^5 - 154*e^3 + 63*e, -5*e^6 + 57*e^4 - 149*e^2 + 73, 9/2*e^7 - 48*e^5 + 115*e^3 - 107/2*e]; heckeEigenvalues := AssociativeArray(); for i := 1 to #heckeEigenvaluesArray do heckeEigenvalues[primes[i]] := heckeEigenvaluesArray[i]; end for; ALEigenvalues := AssociativeArray(); 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;