/* 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![9, -1, -7, 0, 1]; F := NumberField(g); ZF := Integers(F); NN := ideal; primesArray := [ [2, 2, -w^2 + w + 4], [3, 3, -w^2 + w + 3], [5, 5, w^2 - 4], [8, 2, w^3 - w^2 - 4*w + 5], [17, 17, -w^2 + w + 5], [27, 3, -w^3 + 4*w - 2], [29, 29, -w^2 + w + 1], [29, 29, -w^3 + 4*w + 2], [37, 37, -2*w^3 + 3*w^2 + 9*w - 13], [41, 41, w^3 - w^2 - 5*w + 2], [43, 43, -w^3 + w^2 + 3*w - 4], [61, 61, w^2 - 2*w - 2], [61, 61, 2*w^2 - w - 8], [67, 67, -4*w^3 + 5*w^2 + 18*w - 22], [73, 73, -w^2 - 2*w + 2], [79, 79, w^2 - 2*w - 4], [89, 89, w^2 + w - 5], [89, 89, 2*w^3 - 2*w^2 - 9*w + 8], [89, 89, w^3 - 5*w - 5], [89, 89, -w^3 + 2*w^2 + 4*w - 4], [97, 97, w^3 + w^2 - 5*w - 4], [101, 101, -2*w^3 + 2*w^2 + 8*w - 11], [103, 103, w^3 - 5*w + 1], [109, 109, 2*w - 1], [109, 109, -w^3 + 2*w^2 + 3*w - 7], [113, 113, 2*w^2 - 7], [125, 5, -w^3 + 3*w^2 + 3*w - 8], [127, 127, 2*w^3 - 4*w^2 - 11*w + 16], [131, 131, 3*w^2 + 2*w - 8], [131, 131, -2*w^3 + 4*w^2 + 8*w - 13], [137, 137, w^3 - 3*w^2 - 7*w + 10], [149, 149, -w^3 + 4*w - 4], [149, 149, w^2 - 2*w - 8], [157, 157, -w - 4], [163, 163, -w^3 + 2*w^2 + 6*w - 10], [167, 167, -w^3 + 2*w^2 + 5*w - 11], [167, 167, -3*w^2 - 2*w + 10], [167, 167, -w^2 - w + 7], [167, 167, 2*w^2 - 2*w - 5], [173, 173, -3*w^3 + 2*w^2 + 13*w - 11], [179, 179, w^3 - 3*w^2 - 5*w + 10], [191, 191, -2*w^3 - 3*w^2 + 10*w + 14], [191, 191, 3*w^2 + w - 7], [193, 193, w^2 - w + 1], [193, 193, -w^2 - w - 1], [227, 227, 4*w^3 - 4*w^2 - 17*w + 20], [227, 227, -3*w^3 + 4*w^2 + 13*w - 17], [229, 229, -w^3 + 6*w - 2], [233, 233, -3*w^3 + 3*w^2 + 13*w - 16], [241, 241, -w^2 + 2*w - 2], [263, 263, 2*w^3 - 5*w^2 - 12*w + 16], [263, 263, -3*w^3 + 4*w^2 + 13*w - 19], [269, 269, w^3 + 2*w^2 - 5*w - 7], [269, 269, -w^3 - 2*w^2 + w + 5], [281, 281, 2*w^3 - 2*w^2 - 8*w + 1], [281, 281, w^2 - 8], [289, 17, 2*w^3 - 10*w - 7], [307, 307, w^3 + 2*w^2 - 6*w - 8], [307, 307, -2*w^3 + 2*w^2 + 8*w - 7], [313, 313, 5*w^3 - 6*w^2 - 24*w + 28], [313, 313, 2*w^3 - 2*w^2 - 10*w + 5], [337, 337, w^3 - 2*w - 2], [347, 347, -w^3 + 4*w^2 + w - 13], [349, 349, -2*w^3 + w^2 + 9*w - 7], [353, 353, 2*w^3 + w^2 - 7*w + 1], [359, 359, -3*w^2 - 3*w + 5], [359, 359, 3*w^3 - 5*w^2 - 13*w + 16], [367, 367, 3*w^3 - 6*w^2 - 15*w + 23], [367, 367, -w^3 + 2*w^2 + 6*w - 4], [367, 367, -2*w^3 + 2*w^2 + 8*w - 5], [367, 367, 2*w^3 - 3*w^2 - 12*w + 16], [373, 373, -2*w^3 + 4*w^2 + 12*w - 17], [373, 373, 3*w^2 + 4*w - 8], [383, 383, -w^3 + 2*w^2 + 3*w - 13], [383, 383, 2*w^2 - 2*w - 11], [389, 389, 5*w^3 - 6*w^2 - 24*w + 26], [389, 389, -w^3 + 3*w - 5], [401, 401, w^3 + 2*w^2 - 4*w - 10], [401, 401, 2*w^3 - w^2 - 7*w + 5], [409, 409, -2*w^2 + 3*w + 10], [419, 419, w^2 - 3*w - 1], [419, 419, -w^3 + 5*w^2 + 9*w - 14], [421, 421, 2*w^3 - 8*w - 7], [431, 431, -3*w^2 + 16], [431, 431, -3*w^3 + 11*w - 7], [433, 433, 4*w^3 - 7*w^2 - 18*w + 26], [439, 439, 3*w - 2], [439, 439, -w^3 + w^2 + 5*w - 8], [443, 443, 2*w^3 - w^2 - 6*w + 4], [443, 443, w^2 + 3*w - 1], [449, 449, -2*w^3 + 5*w^2 + 7*w - 17], [457, 457, 4*w^3 - 6*w^2 - 19*w + 22], [479, 479, 3*w^2 - 3*w - 13], [479, 479, -4*w^3 + 8*w^2 + 22*w - 31], [479, 479, 3*w^3 - 7*w^2 - 17*w + 26], [479, 479, -6*w^3 + 7*w^2 + 28*w - 32], [487, 487, -2*w^3 + 4*w^2 + 7*w - 8], [491, 491, 3*w^2 - w - 11], [491, 491, 4*w^3 - 5*w^2 - 18*w + 20], [521, 521, -3*w^3 + 11*w - 5], [521, 521, 3*w^3 - 3*w^2 - 15*w + 14], [523, 523, -2*w^3 + 5*w^2 + 8*w - 14], [529, 23, -2*w^3 + 3*w^2 + 8*w - 14], [529, 23, 3*w^3 - 2*w^2 - 14*w + 4], [541, 541, -w^3 + 2*w^2 + 7*w - 11], [541, 541, -w^3 - w^2 + 5*w - 2], [547, 547, -3*w - 2], [547, 547, w^3 - 2*w^2 - 7*w + 7], [547, 547, w^3 - 4*w^2 - 8*w + 10], [547, 547, 2*w^3 - 3*w^2 - 7*w + 11], [563, 563, 2*w^3 - 4*w^2 - 12*w + 13], [563, 563, -w^3 + 4*w^2 + w - 7], [571, 571, -w^3 + 2*w^2 + 2*w - 8], [571, 571, 3*w^2 - 10], [577, 577, 2*w^3 + w^2 - 7*w - 5], [599, 599, 2*w^3 - 7*w + 2], [599, 599, -4*w^3 + 7*w^2 + 21*w - 29], [617, 617, -2*w^3 + w^2 + 11*w + 1], [631, 631, 3*w^2 + w - 13], [631, 631, 3*w^2 - 4*w - 10], [647, 647, 3*w^3 - 4*w^2 - 13*w + 11], [677, 677, -2*w^3 + 4*w^2 + 8*w - 17], [691, 691, -w^3 + 3*w^2 + 3*w - 14], [733, 733, -w^3 + 4*w^2 + 3*w - 11], [733, 733, 3*w^3 - w^2 - 15*w - 2], [733, 733, -w^3 + w^2 + 7*w - 2], [733, 733, 3*w^3 - 4*w^2 - 16*w + 16], [739, 739, -3*w^3 + w^2 + 11*w - 8], [743, 743, -3*w^3 + 2*w^2 + 12*w - 14], [751, 751, -2*w^3 + w^2 + 8*w - 2], [761, 761, -2*w^3 + 2*w^2 + 7*w - 10], [761, 761, 2*w^3 - 4*w^2 - 3*w + 8], [769, 769, -w^3 + w^2 + 7*w - 4], [769, 769, 2*w^3 + 2*w^2 - 8*w - 11], [787, 787, -2*w^3 + 3*w^2 + 6*w - 10], [787, 787, -2*w^2 - 3*w + 8], [797, 797, -2*w^3 + w^2 + 7*w - 1], [797, 797, -2*w^3 - 2*w^2 + 11*w + 10], [809, 809, -2*w^3 + 5*w^2 + 7*w - 19], [811, 811, 2*w^3 - 2*w^2 - 7*w - 2], [811, 811, 3*w^3 - 2*w^2 - 11*w - 1], [827, 827, 3*w^3 - 2*w^2 - 14*w + 10], [829, 829, 2*w^3 - 2*w^2 - 9*w + 2], [829, 829, 4*w^2 + 2*w - 11], [841, 29, 2*w^3 + w^2 - 6*w - 2], [863, 863, 2*w^3 - 8*w - 1], [883, 883, 3*w^3 - 4*w^2 - 15*w + 13], [887, 887, 3*w^3 - 2*w^2 - 12*w + 10], [907, 907, 2*w^3 - 3*w^2 - 9*w + 7], [911, 911, 2*w^3 + w^2 - 11*w - 5], [919, 919, -2*w^3 + 5*w - 8], [929, 929, -w^3 + 4*w^2 + 3*w - 13], [937, 937, w^3 - 5*w - 7], [937, 937, -2*w^3 + 3*w^2 + 10*w - 8], [971, 971, -2*w^3 + 4*w^2 + 11*w - 20], [971, 971, -4*w^3 + 4*w^2 + 19*w - 20], [977, 977, -4*w^3 + 6*w^2 + 19*w - 28], [983, 983, -4*w^2 - 4*w + 7], [991, 991, -5*w^3 + 8*w^2 + 26*w - 32], [991, 991, -6*w^3 + 6*w^2 + 26*w - 31], [997, 997, -3*w^3 + 8*w^2 + 18*w - 26]]; primes := [ideal : I in primesArray]; heckePol := x^3 - 3*x^2 + 1; K := NumberField(heckePol); heckeEigenvaluesArray := [-1, e, -1, 2*e^2 - 4*e, 3*e^2 - 7*e - 1, -e^2 + 5*e - 1, -e^2 + 4, 2*e^2 - 3*e - 8, -5*e^2 + 10*e + 4, 5*e^2 - 7*e - 9, -2*e^2 + 10*e - 2, 4*e^2 - 12*e - 6, -2*e^2 + 2*e + 2, -6*e^2 + 21*e - 2, 8*e^2 - 22*e + 2, 3*e + 2, 6*e^2 - 22*e - 4, 2*e^2 - 6*e - 8, 2*e^2 - 14*e + 8, -2*e^2 + 6*e + 2, -e^2 + e + 15, 2*e^2 - 3*e + 4, -e^2 - 6*e + 6, -13*e^2 + 32*e + 4, 8*e^2 - 20*e, -8*e^2 + 22*e + 6, -6*e + 6, -2*e^2 + 4*e - 8, -4*e^2 + 8*e - 6, -6*e^2 + 16*e - 8, 2*e^2 - 9*e - 8, -8*e^2 + 22*e, 8*e^2 - 22*e + 6, 5*e^2 - 14*e - 8, -9*e^2 + 16*e + 14, 8*e^2 - 30*e + 4, -10*e^2 + 36*e - 2, -7*e^2 + 15*e + 1, 2*e^2 - 8*e + 14, 17*e^2 - 37*e - 9, 10*e^2 - 28*e - 8, -5*e^2 + 16*e, 12*e^2 - 30*e + 6, -12*e^2 + 30*e + 8, -7*e^2 + 28*e + 4, -7*e^2 + 15*e + 19, 2*e^2 - 14*e + 20, 2*e - 18, 12*e^2 - 36*e, -5*e^2 + 10*e + 16, 4*e^2 - 16*e + 4, -6*e^2 + 14*e + 2, 12*e^2 - 42*e, -9*e^2 + 23*e - 7, -12*e^2 + 42*e + 6, 9*e^2 - 16*e + 2, 14*e^2 - 42*e + 2, -5*e^2 + 8*e + 18, -6*e^2 + 18*e - 8, -8*e^2 + 20*e + 6, -6*e + 4, 4*e^2 - 2*e - 4, -9*e^2 + 8*e + 26, -10, -10*e^2 + 36*e - 2, 4*e^2 - 11*e, -11*e^2 + 14*e + 28, -12*e^2 + 33*e + 10, -8*e^2 + 20*e + 6, -6*e^2 - 2*e + 36, 14*e^2 - 32*e - 18, e^2 + 9*e - 17, -8*e^2 + 16*e - 16, -8*e^2 + 13*e + 18, -11*e^2 + 27*e + 23, -3*e^2 + 7*e + 13, -12*e^2 + 44*e - 10, 15*e^2 - 35*e - 11, -2*e^2 - 17*e + 30, 2*e^2 - 17*e + 18, -2*e^2 + 2*e - 2, 5*e^2 - 29*e + 17, -9*e^2 + 15*e + 25, -8*e^2 + 16*e + 12, -10*e^2 + 44*e - 12, 6*e^2 - 19*e + 18, 14*e^2 - 29*e + 4, -5*e^2 + 23*e + 11, 9*e^2 - 30*e + 12, -3*e + 24, 2*e^2 + 6*e - 8, -6*e^2 + 6*e + 14, -10*e^2 + 14*e + 6, 8*e^2 - 20*e - 28, -5*e^2 + 14*e + 16, 28*e^2 - 68*e - 6, -e^2 + 8*e + 4, -6*e^2 + 6*e + 18, 4*e^2 - 20*e - 6, -11*e^2 + 16*e + 6, 14*e^2 - 36*e - 20, -3*e^2 + 3*e - 5, 13*e^2 - 34*e - 6, 14*e^2 - 40*e + 4, -12*e^2 + 36*e - 10, -2*e^2 - 10*e + 26, -11*e^2 + 24*e + 24, 5*e^2 - 38*e + 24, 8*e^2 - 38*e + 16, 14*e^2 - 28*e - 28, 4*e^2 - 20*e + 6, 12*e - 12, 12*e^2 - 9*e - 34, 4*e^2 - 32, -16*e^2 + 44*e + 4, -6*e^2 - 8*e + 34, 10*e^2 - 43*e + 16, 2*e^2 - 19*e + 12, 18*e^2 - 42*e - 20, -10*e^2 + 20*e + 2, 20*e^2 - 69*e - 2, -11*e^2 + 36*e + 8, 11*e^2 - 34*e + 8, 12*e^2 - 24*e - 8, -20*e^2 + 41*e + 24, 4*e^2 - 22*e + 30, 2*e^2 + 13*e - 6, -2*e^2 + 3*e + 16, 11*e^2 - 33*e + 13, 2*e^2 + 12*e - 6, 20*e^2 - 60*e + 4, -6*e^2 + 4*e + 52, -26*e^2 + 71*e - 4, -2*e^2 + 22, -16*e^2 + 46*e - 24, -20*e^2 + 43*e - 4, -4*e^2 + 16*e + 2, 8*e^2 - 14*e + 8, -28*e^2 + 68*e - 6, -15*e^2 + 26*e, 5*e^2 + e - 17, 25*e^2 - 63*e + 11, 14*e^2 - 32*e + 24, -7*e - 12, -14*e^2 + 20*e + 38, 8*e^2 + 4*e - 22, -5*e^2 + 20*e - 36, 5*e^2 - 9*e + 19, -11*e^2 + 23*e - 9, -16*e^2 + 56*e - 12, 8*e^2 - 34*e + 14, 18*e^2 - 52*e + 8, -8*e^2 + 58, -6*e^2 + 8*e + 12, 30*e^2 - 74*e - 2, -14*e^2 + 48*e + 14, -10*e^2 + 30*e + 4, -7*e^2 + 28*e - 4, 8*e^2 - 20*e + 4, -15*e^2 + 54*e - 22, -16*e^2 + 40*e - 18]; 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;