/* 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![-3, -7, 0, 1]; F := NumberField(g); ZF := Integers(F); NN := ideal; primesArray := [ [3, 3, w], [3, 3, w + 1], [3, 3, w + 2], [8, 2, 2], [11, 11, -w^2 + 5], [13, 13, w^2 - w - 7], [17, 17, -w^2 + w + 4], [19, 19, -w^2 - w + 4], [29, 29, 2*w^2 - 2*w - 11], [31, 31, w^2 - 2*w - 4], [37, 37, -2*w^2 + 3*w + 7], [41, 41, w^2 - 2], [59, 59, 2*w^2 - 13], [61, 61, w^2 + w - 10], [67, 67, 2*w^2 - w - 11], [73, 73, -w^2 - 1], [83, 83, w^2 - w - 10], [89, 89, -w^2 + 4*w - 2], [97, 97, w^2 - 2*w - 7], [97, 97, -w^2 - 4*w - 5], [97, 97, 2*w^2 + w - 8], [101, 101, -4*w^2 + 2*w + 25], [103, 103, w^2 + w - 7], [107, 107, -3*w - 4], [109, 109, 5*w^2 - 3*w - 31], [121, 11, 2*w^2 - 3*w - 4], [125, 5, -5], [137, 137, -5*w^2 + 3*w + 34], [139, 139, w^2 + 2*w - 4], [151, 151, 3*w^2 - 23], [151, 151, w^2 - 3*w - 5], [151, 151, 3*w^2 - 3*w - 17], [157, 157, 4*w^2 - 9*w - 8], [157, 157, w^2 + 3*w - 2], [157, 157, 2*w^2 - w - 2], [167, 167, 2*w^2 + w - 11], [167, 167, -w^2 + 11], [167, 167, -3*w^2 + 19], [169, 13, w^2 - 4*w - 4], [173, 173, 2*w^2 - 3*w - 10], [179, 179, -3*w + 7], [191, 191, -w^2 + 5*w - 5], [193, 193, -w^2 + w - 2], [199, 199, 3*w - 2], [211, 211, w^2 - 3*w - 11], [223, 223, 3*w^2 - 20], [223, 223, w^2 - 5*w - 4], [223, 223, 2*w^2 - w - 8], [229, 229, 4*w^2 - 3*w - 26], [229, 229, 2*w^2 + w - 20], [229, 229, 2*w^2 - 2*w - 5], [239, 239, -6*w^2 + 3*w + 38], [241, 241, -w^2 + 4*w - 5], [257, 257, -2*w^2 + 5*w - 1], [263, 263, -2*w^2 - w + 17], [269, 269, -w^2 - w + 13], [269, 269, 3*w - 4], [269, 269, -4*w^2 + w + 31], [271, 271, 2*w^2 - 7], [271, 271, 3*w - 5], [271, 271, w^2 - 3*w - 8], [289, 17, 2*w^2 + w - 5], [307, 307, 2*w^2 - w - 5], [311, 311, 3*w^2 - 3*w - 19], [311, 311, -7*w^2 + 13*w + 19], [311, 311, w^2 - 2*w - 13], [313, 313, w^2 + 2*w - 7], [317, 317, -5*w^2 + w + 35], [331, 331, -w^2 + 3*w - 4], [337, 337, 3*w^2 - 3*w - 13], [343, 7, -7], [347, 347, 2*w^2 - 3*w - 13], [349, 349, 3*w^2 - 3*w - 20], [359, 359, -w^2 + 5*w - 2], [361, 19, -2*w^2 + 7*w - 1], [389, 389, -2*w^2 + w - 1], [397, 397, w^2 - 6*w + 10], [401, 401, 6*w^2 - 3*w - 44], [419, 419, -3*w^2 + 6*w + 10], [419, 419, 4*w^2 - 2*w - 31], [419, 419, -4*w^2 + 4*w + 19], [421, 421, 6*w^2 - 12*w - 13], [431, 431, 4*w^2 - 7*w - 10], [433, 433, w^2 - 4*w - 7], [443, 443, 2*w^2 + 4*w - 5], [443, 443, 5*w^2 - 11*w - 11], [443, 443, 3*w^2 - 14], [449, 449, -2*w^2 + 2*w - 1], [457, 457, w^2 - 6*w - 5], [457, 457, w^2 + 3*w - 5], [457, 457, 6*w^2 - 3*w - 37], [463, 463, w^2 + 5*w - 1], [467, 467, w^2 - w - 13], [479, 479, 5*w^2 - 9*w - 16], [487, 487, -6*w - 5], [499, 499, 3*w^2 - 3*w - 4], [499, 499, 3*w^2 + 3*w - 1], [499, 499, w^2 - 5*w + 8], [503, 503, 4*w^2 - 5*w - 16], [509, 509, 2*w^2 - 5*w - 8], [521, 521, 4*w^2 - w - 22], [523, 523, w^2 - 5*w - 16], [547, 547, 5*w^2 - 2*w - 38], [547, 547, 8*w^2 - 3*w - 58], [547, 547, 4*w^2 - 29], [557, 557, 7*w^2 - 4*w - 43], [557, 557, 3*w - 11], [557, 557, 2*w^2 - 4*w - 11], [569, 569, 5*w^2 - 4*w - 32], [569, 569, 3*w^2 - 3*w - 11], [569, 569, w^2 + 2*w - 16], [571, 571, w^2 - 4*w - 10], [593, 593, 2*w^2 - 6*w - 7], [601, 601, -w^2 - 3*w + 14], [607, 607, 3*w^2 + 3*w - 7], [619, 619, 3*w^2 - 6*w - 11], [631, 631, -w^2 - w - 5], [641, 641, 3*w^2 - 3*w - 5], [647, 647, -w^2 + 6*w - 1], [653, 653, -5*w^2 + 4*w + 35], [661, 661, 3*w^2 - 3*w - 10], [673, 673, w^2 + 4*w - 4], [677, 677, 5*w^2 - 6*w - 25], [677, 677, w^2 - 14], [677, 677, 4*w^2 - 3*w - 20], [691, 691, 5*w^2 - 2*w - 29], [701, 701, 5*w^2 - 10*w - 14], [719, 719, -3*w - 11], [727, 727, -2*w^2 + 9*w - 8], [733, 733, -w^2 - 4*w - 8], [739, 739, w^2 + 3*w - 8], [743, 743, 2*w^2 - 4*w - 17], [757, 757, -w^2 + w - 5], [769, 769, 3*w^2 - 3*w - 7], [769, 769, -w^2 - 3*w - 7], [769, 769, 5*w^2 - 3*w - 28], [773, 773, 7*w^2 - 6*w - 38], [787, 787, 2*w^2 - w - 20], [797, 797, -5*w^2 + 14*w - 1], [821, 821, -w^2 + 6*w - 4], [823, 823, 7*w^2 - 6*w - 41], [839, 839, 4*w^2 - 6*w - 11], [841, 29, 5*w^2 - 4*w - 26], [857, 857, 3*w^2 - 11], [863, 863, 2*w^2 + 2*w - 17], [881, 881, 5*w^2 - 5*w - 29], [883, 883, -4*w^2 + 8*w + 13], [907, 907, 4*w^2 - 9*w - 11], [911, 911, 2*w^2 + 3*w - 10], [947, 947, 2*w^2 + 5*w - 5], [953, 953, 2*w^2 - 5*w - 11], [961, 31, w^2 - 5*w - 13], [967, 967, 2*w^2 - 3*w - 22], [967, 967, 5*w^2 - 9*w - 10], [967, 967, 3*w^2 - 10], [977, 977, 5*w^2 - 37], [983, 983, 7*w^2 - 5*w - 40], [997, 997, -7*w^2 + 5*w + 49]]; primes := [ideal : I in primesArray]; heckePol := x^4 - 3*x^3 - 3*x^2 + 11*x - 5; K := NumberField(heckePol); heckeEigenvaluesArray := [e, -e^3 + 2*e^2 + 5*e - 6, e, -e + 2, 1, 2*e^3 - 4*e^2 - 10*e + 12, -2*e^3 + 4*e^2 + 9*e - 9, -3*e^3 + 5*e^2 + 15*e - 16, e^3 - 2*e^2 - 5*e + 7, -e^3 + 3*e + 7, 2*e^3 - 4*e^2 - 7*e + 13, -e^3 + 3*e^2 + 6*e - 10, -5*e^3 + 10*e^2 + 24*e - 30, 4*e^3 - 9*e^2 - 21*e + 23, -e^3 + 2*e^2 + 5*e + 3, -2*e^2 + 3*e + 6, 5*e^3 - 10*e^2 - 21*e + 30, 4*e^3 - 9*e^2 - 22*e + 33, e^3 + e^2 - 9*e - 1, -5*e^3 + 7*e^2 + 23*e - 17, 4*e^3 - 7*e^2 - 20*e + 23, -4*e^3 + 8*e^2 + 17*e - 25, 2*e^3 - e^2 - 9*e - 5, -e^3 + 4*e^2 - e - 9, 2*e^3 - 3*e^2 - 10*e + 15, -e^2 + 4*e + 1, -2*e^3 + 6*e^2 + 8*e - 6, 6*e^3 - 11*e^2 - 27*e + 38, -3*e^3 + 6*e^2 + 19*e - 27, 5*e^3 - 11*e^2 - 20*e + 33, -3*e^3 + 7*e^2 + 13*e - 29, e^3 - 6*e^2 - e + 23, -7*e^3 + 10*e^2 + 32*e - 23, e^3 - 4*e^2 - 4*e + 9, -2*e^3 + 6*e^2 + 9*e - 22, -7*e^3 + 12*e^2 + 35*e - 35, 4*e^3 - 7*e^2 - 16*e + 22, -5*e^3 + 9*e^2 + 18*e - 14, 5*e^3 - 8*e^2 - 27*e + 20, -e^3 - 2*e^2 + 3*e + 16, -e^3 + 3*e^2 + 3*e - 25, -2*e^3 + 5*e^2 + 7*e - 30, e^3 + e^2 - 11*e - 7, 6*e^3 - 11*e^2 - 24*e + 33, e^3 - 5*e^2 - 2*e + 5, e^3 + 3*e^2 - 12*e - 16, -3*e^3 + 6*e^2 + 18*e - 16, 3*e^3 - 2*e^2 - 15*e + 3, 2*e^3 - 5*e^2 - 11*e + 6, -10*e^3 + 20*e^2 + 46*e - 52, e^2 + 16, 10*e^3 - 20*e^2 - 48*e + 57, -e^3 + 4*e^2 - 22, e^3 - 5*e^2 - e + 14, 6*e^3 - 13*e^2 - 28*e + 24, 7*e^3 - 8*e^2 - 38*e + 25, 9*e^3 - 19*e^2 - 35*e + 50, 2*e^3 - 6*e^2 - 15*e + 23, -2*e^3 + 13*e + 7, 7*e^3 - 16*e^2 - 35*e + 55, 6*e^3 - 10*e^2 - 33*e + 26, e^2 - 4*e + 15, -6*e^2 + 8*e + 9, -2*e^3 + 8*e^2 + 7*e - 24, -2*e^3 + 20*e - 3, 3*e^3 - 4*e^2 - 21*e + 4, 9*e^3 - 17*e^2 - 40*e + 60, 6*e^3 - 12*e^2 - 35*e + 46, 7*e^3 - 14*e^2 - 33*e + 31, 3*e^3 - 4*e^2 - 30*e + 11, -2*e^3 - 3*e^2 + 8*e + 26, 12*e^3 - 23*e^2 - 53*e + 72, -4*e^3 + 7*e^2 + 18*e - 18, e^3 - 3*e^2 - 14*e + 26, -5*e^3 + 13*e^2 + 24*e - 29, 11*e^3 - 19*e^2 - 55*e + 56, 6*e^3 - 7*e^2 - 27*e + 14, 4*e^3 - 8*e^2 - 14*e + 22, -3*e^3 + 9*e^2 + 17*e - 40, 6*e^3 - 12*e^2 - 32*e + 37, 11*e^3 - 24*e^2 - 42*e + 59, -3*e^3 + 3*e^2 + 21*e - 2, -2*e^3 - 2*e^2 + 3*e + 30, e^3 + 3*e^2 - 17*e - 6, 2*e^3 - 11*e^2 - 3*e + 31, 2*e^2 + 10*e - 13, -e^3 - 2*e^2 + 10*e + 5, -2*e^3 + 7*e^2 + 4*e - 23, -5*e^3 + 5*e^2 + 26*e - 22, e^3 - e^2 - 14*e + 26, 2*e^3 - 11*e^2 - 3*e + 23, 10*e^3 - 17*e^2 - 38*e + 39, e^3 - e^2 - 5*e, 5*e^3 - 5*e^2 - 28*e, 15*e^3 - 26*e^2 - 74*e + 86, -2*e^3 + e^2 + 15*e - 20, 9*e^3 - 22*e^2 - 27*e + 65, -7*e^3 + 17*e^2 + 31*e - 42, -6*e^3 + 4*e^2 + 28*e - 3, -10*e^3 + 27*e^2 + 41*e - 62, 14*e^3 - 29*e^2 - 56*e + 83, -6*e^3 + 22*e^2 + 21*e - 56, 9*e^3 - 19*e^2 - 38*e + 54, 9*e^3 - 17*e^2 - 50*e + 37, -3*e^3 + e^2 + 19*e - 1, -11*e^3 + 23*e^2 + 45*e - 67, -5*e^3 + 7*e^2 + 40*e - 32, 4*e^3 - 16*e^2 - 12*e + 56, -e^3 + 14*e^2 - 7*e - 46, -15*e^3 + 35*e^2 + 65*e - 93, 3*e^3 - 4*e^2 - 6*e + 4, -5*e^2 - 7*e + 20, 5*e + 2, -12*e^3 + 20*e^2 + 62*e - 67, -10*e^3 + 19*e^2 + 49*e - 33, -13*e^3 + 24*e^2 + 52*e - 64, 3*e^3 + 2*e^2 - 22*e - 10, 5*e^2 - 8*e + 11, -6*e^3 + 4*e^2 + 33*e + 11, -7*e^3 + 18*e^2 + 21*e - 40, 9*e^3 - 10*e^2 - 44*e + 15, 6*e^3 - 9*e^2 - 30*e + 4, -4*e^3 + 11*e^2 + 16*e - 32, -10*e^3 + 12*e^2 + 61*e - 42, 11*e^3 - 17*e^2 - 52*e + 69, -e^3 + 7*e^2 + e - 20, 7*e^3 - 11*e^2 - 25*e + 35, -9*e^3 + 21*e^2 + 43*e - 59, -8*e^3 + 11*e^2 + 35*e - 33, 4*e^3 - e^2 - 12*e - 8, 7*e^3 - 13*e^2 - 37*e + 54, -e^3 + 5*e^2 - 9, 4*e^3 - 11*e^2 - 26*e + 56, -9*e^3 + 14*e^2 + 58*e - 45, -21*e^3 + 43*e^2 + 91*e - 104, 5*e^3 - 14*e^2 - 19*e + 35, 11*e^3 - 24*e^2 - 63*e + 68, -12*e^3 + 21*e^2 + 58*e - 57, -e^3 - 8*e^2 + 9*e + 52, 11*e^3 - 20*e^2 - 54*e + 49, 12*e^3 - 24*e^2 - 56*e + 59, -3*e^3 + 7*e^2 + e + 3, -5*e^3 + e^2 + 41*e + 3, -6*e^3 + 8*e^2 + 39*e - 32, 5*e^3 - 5*e^2 - 32*e + 26, -e^2 + 5*e + 9, 6*e^3 + 5*e^2 - 44*e - 20, -11*e^3 + 19*e^2 + 56*e - 27, 2*e^3 - 11*e + 3, 5*e^3 + 3*e^2 - 37*e + 13, 2*e^3 - e^2 - 18*e + 12, -6*e^3 + 6*e^2 + 42*e - 7, 14*e^3 - 33*e^2 - 50*e + 85, -8*e^3 + 22*e^2 + 28*e - 51, 7*e^3 - 21*e^2 - 20*e + 78, -7*e^3 + 22*e^2 + 35*e - 78, -12*e^3 + 33*e^2 + 57*e - 93, -7*e^3 + 15*e^2 + 30*e - 47]; 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;