/* 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, -6, 0, 1]; F := NumberField(g); ZF := Integers(F); NN := ideal; primesArray := [ [2, 2, w + 1], [3, 3, w], [4, 2, -w^2 + w + 5], [7, 7, -w + 2], [19, 19, -2*w^2 + w + 10], [23, 23, -w^2 + 8], [23, 23, -w^2 + 2], [29, 29, -w^2 + 2*w + 4], [37, 37, w^2 - 2*w - 8], [41, 41, 4*w^2 - 3*w - 20], [43, 43, -w - 4], [47, 47, 2*w - 1], [49, 7, -2*w^2 + 3*w + 4], [59, 59, 2*w^2 - 13], [61, 61, -3*w^2 + 4*w + 10], [67, 67, 2*w^2 - 2*w - 7], [71, 71, -3*w - 4], [79, 79, 2*w^2 - 3*w - 8], [83, 83, 2*w^2 - w - 14], [83, 83, -4*w^2 + 3*w + 22], [83, 83, 2*w^2 - w - 8], [97, 97, 4*w^2 - 2*w - 25], [101, 101, 3*w^2 - 2*w - 14], [103, 103, 2*w^2 - 7], [109, 109, 2*w^2 + 2*w - 1], [113, 113, w^2 - 4*w - 4], [113, 113, 4*w^2 - 4*w - 17], [113, 113, 2*w^2 - 2*w - 5], [125, 5, -5], [131, 131, -5*w^2 + 2*w + 26], [137, 137, 3*w^2 - 2*w - 20], [137, 137, -w^2 + 2*w - 2], [137, 137, -w^2 - 2], [149, 149, w^2 + 2*w - 4], [149, 149, 2*w^2 + w - 2], [149, 149, 4*w^2 - 4*w - 19], [151, 151, w^2 - 10], [151, 151, -6*w^2 + 4*w + 31], [151, 151, 2*w^2 - 3*w - 14], [157, 157, 2*w^2 + w - 4], [163, 163, 4*w + 5], [163, 163, 2*w^2 - w - 4], [163, 163, 3*w^2 - 20], [167, 167, 2*w^2 - 3*w - 10], [173, 173, 2*w^2 - 5], [179, 179, -3*w^2 + 16], [181, 181, 3*w - 2], [197, 197, 3*w^2 - 4*w - 8], [199, 199, -2*w - 7], [229, 229, -w^2 - 2*w - 4], [233, 233, 3*w - 4], [239, 239, 5*w^2 - 2*w - 32], [241, 241, 2*w^2 + 1], [257, 257, w^2 + 2*w - 10], [269, 269, -5*w^2 + 4*w + 28], [283, 283, 2*w^2 + w - 14], [307, 307, -6*w - 5], [307, 307, -3*w^2 + 4*w + 14], [307, 307, 2*w^2 - w - 16], [311, 311, -w^2 - 2*w + 14], [313, 313, -2*w^2 + 4*w - 1], [317, 317, 3*w^2 + 4*w - 2], [337, 337, w^2 - 4*w - 8], [347, 347, -8*w^2 + 3*w + 46], [353, 353, 2*w^2 - 17], [361, 19, -3*w^2 + 2*w + 4], [367, 367, 2*w^2 + 5*w - 2], [373, 373, -2*w^2 + 2*w - 1], [379, 379, 3*w^2 - 4*w - 20], [397, 397, -w^2 + 2*w - 4], [397, 397, 3*w^2 - 10], [397, 397, 3*w^2 - 2*w - 10], [409, 409, -w^2 - 4], [409, 409, -4*w^2 + 4*w + 23], [409, 409, 2*w^2 - 5*w - 8], [421, 421, 2*w^2 - 4*w - 11], [433, 433, 8*w^2 - 4*w - 49], [443, 443, -3*w^2 + 4*w + 16], [449, 449, 6*w^2 - 3*w - 38], [457, 457, -6*w^2 + 5*w + 32], [461, 461, w - 8], [467, 467, -w - 8], [467, 467, 2*w^2 - 4*w - 13], [467, 467, -4*w - 11], [491, 491, 2*w^2 + 6*w - 1], [509, 509, 8*w^2 - 6*w - 43], [521, 521, 4*w^2 - 2*w - 17], [521, 521, 6*w + 7], [521, 521, 4*w - 7], [523, 523, 5*w^2 - 4*w - 22], [541, 541, 6*w^2 - w - 32], [541, 541, 4*w^2 - 8*w - 11], [541, 541, 3*w^2 - 4], [547, 547, 2*w^2 + 2*w - 17], [547, 547, 4*w - 5], [547, 547, -3*w^2 + 8*w + 8], [557, 557, 3*w^2 - 8], [557, 557, 6*w^2 - 4*w - 29], [557, 557, -2*w^2 + w - 2], [571, 571, -2*w^2 - 4*w + 5], [587, 587, 3*w^2 + 2*w + 2], [593, 593, -6*w^2 + 5*w + 34], [599, 599, -w^2 - 8*w - 10], [601, 601, -4*w^2 - 6*w + 1], [601, 601, 4*w^2 - 3*w - 28], [601, 601, 2*w^2 + 2*w - 11], [613, 613, 6*w^2 - w - 38], [617, 617, 2*w^2 - 5*w - 10], [617, 617, -10*w^2 + 6*w + 53], [617, 617, 7*w^2 - 4*w - 44], [619, 619, -3*w^2 - 4*w + 8], [631, 631, 6*w^2 - 6*w - 29], [641, 641, w^2 + 4*w - 4], [641, 641, -6*w^2 + 2*w + 29], [641, 641, -w^2 - 4*w - 8], [643, 643, 4*w^2 - w - 16], [647, 647, 3*w^2 + 6*w - 4], [653, 653, 7*w^2 - 6*w - 32], [661, 661, 4*w^2 - 4*w - 13], [673, 673, 2*w^2 + 8*w + 1], [673, 673, -8*w^2 + 6*w + 47], [673, 673, 2*w^2 + 3*w - 8], [683, 683, 8*w^2 - 7*w - 40], [709, 709, 5*w^2 - 26], [719, 719, 2*w^2 + 2*w - 13], [727, 727, -w^2 + 6*w - 2], [733, 733, w^2 - 6*w - 8], [751, 751, 4*w^2 - 7*w - 14], [757, 757, 4*w^2 - 5*w - 26], [761, 761, 2*w^2 - 5*w - 16], [769, 769, -2*w^2 + 8*w + 1], [787, 787, 5*w^2 - 2*w - 34], [797, 797, 2*w^2 + w - 20], [797, 797, 4*w^2 - 3*w - 14], [797, 797, -8*w^2 + 2*w + 53], [809, 809, -5*w^2 - 2*w + 40], [811, 811, -7*w - 8], [811, 811, 3*w^2 + 2*w - 14], [811, 811, -6*w^2 + 8*w + 19], [821, 821, -6*w^2 + w + 34], [823, 823, 4*w^2 + 2*w - 17], [823, 823, 4*w^2 - 4*w - 7], [823, 823, 4*w^2 - 6*w - 17], [841, 29, 2*w^2 - 5*w - 14], [857, 857, -8*w^2 + 4*w + 41], [859, 859, -10*w^2 + 7*w + 56], [859, 859, 2*w^2 - 19], [859, 859, 5*w^2 - 2*w - 22], [863, 863, 6*w - 1], [887, 887, w^2 - 14], [907, 907, 10*w^2 - 9*w - 46], [911, 911, -7*w - 10], [911, 911, 6*w^2 - 5*w - 26], [911, 911, 5*w - 4], [919, 919, -2*w^2 - 11*w - 8], [929, 929, w^2 - 6*w - 10], [937, 937, w - 10], [947, 947, 5*w^2 - 4*w - 20], [967, 967, -7*w^2 + 6*w + 38], [967, 967, 2*w^2 - 2*w - 19], [967, 967, 8*w^2 - 5*w - 40], [977, 977, 2*w^2 + 3*w - 10], [977, 977, 2*w^2 + 4*w - 7], [977, 977, 2*w^2 - 6*w - 19], [997, 997, -12*w^2 + 7*w + 64], [997, 997, 4*w^2 - 13], [997, 997, 5*w^2 - 32]]; primes := [ideal : I in primesArray]; heckePol := x^4 + x^3 - 5*x^2 - 4*x + 3; K := NumberField(heckePol); heckeEigenvaluesArray := [e, e^2 - 3, -1, -e - 1, e^3 - e^2 - 4*e + 2, -2*e^3 + 7*e - 3, -1, -e^2 + 3, -e^3 - e^2 + 6*e + 2, 2*e^3 + 2*e^2 - 6*e - 6, -2*e^3 + 2*e^2 + 8*e - 4, 2*e^3 - 10*e, -2*e^2 - 4*e + 8, -2*e^3 + e^2 + 6*e + 3, 4*e^3 - 2*e^2 - 16*e + 2, 2*e^3 - 3*e^2 - 8*e + 5, -4*e^2 + 4*e + 12, -3*e^3 - 3*e^2 + 14*e + 8, 2*e^3 - 10*e - 6, 6*e^3 - 2*e^2 - 22*e + 6, e^3 - e^2 - 6*e, 2*e^3 - 4*e + 2, -4*e^3 - e^2 + 20*e + 3, 2*e^3 - 8*e + 2, -2*e^3 + 2*e^2 + 12*e - 4, 4*e^3 + 2*e^2 - 13*e - 3, 2*e^3 - 2*e^2 - 5*e + 3, 2*e^3 - 8*e + 6, -2*e^3 + 4*e, e^3 - 3*e^2 - 8*e + 6, -4*e^2 + 18, 2*e^3 - 4*e^2 - 8*e + 6, -6*e^2 - 2*e + 12, -4*e^3 - 4*e^2 + 8*e + 12, -4*e^3 + 6*e^2 + 18*e - 18, -2*e^3 + 6*e^2 + 8*e - 12, -2*e^3 + 2*e^2 + 8*e - 16, 4*e^3 + 2*e^2 - 12*e - 10, 2*e^3 + e^2 - 4*e - 7, 2*e^3 + 2*e^2 - 7*e - 7, -4*e^3 + 4*e^2 + 12*e - 16, -8*e^3 - 4*e^2 + 28*e + 8, -3*e^3 + e^2 + 16*e - 10, -4*e^3 + 14*e + 6, -8*e^3 + 2*e^2 + 32*e, 6*e^3 - 21*e - 9, -2*e^3 - 2*e^2 + 5*e + 5, -4*e^3 + 4*e^2 + 18*e, 4*e^3 + 4*e^2 - 12*e - 16, -6*e^3 + 2*e^2 + 20*e - 10, -4*e^3 - 2*e^2 + 23*e + 9, -2*e^3 + 4*e^2 + 2*e - 12, e^2 - 4*e - 19, -2*e^3 + 2*e^2 + 7*e - 9, -4*e^3 + 6*e^2 + 9*e - 33, -2*e^3 + 14*e - 16, 4*e^3 + 3*e^2 - 14*e + 5, 6*e^3 - 2*e^2 - 16*e + 20, 6*e^3 + 6*e^2 - 22*e - 10, -7*e^3 + 5*e^2 + 22*e - 24, -2*e^3 + 2*e^2 + 10*e - 4, 3*e^3 + 3*e^2 - 16*e - 12, -2*e^3 - 4*e^2 + 14*e + 8, -4*e^3 + 3*e^2 + 10*e - 27, 4*e^3 + 6*e^2 - 12*e - 12, -6*e^3 - 4*e^2 + 28*e + 8, -8*e^2 - 10*e + 26, 8*e^3 + e^2 - 46*e - 13, 4*e^2 + 7*e - 19, 8*e^3 - 5*e^2 - 36*e + 11, 12*e^3 + 2*e^2 - 48*e - 10, -12*e^3 + 4*e^2 + 40*e - 16, -7*e^2 + 2*e - 1, -8*e^3 + 4*e^2 + 26*e - 10, -4*e^3 - 8*e^2 + 22*e + 14, 12*e^3 + 5*e^2 - 48*e - 19, -2*e^3 + 8*e^2 + 16*e - 16, 7*e^3 - 5*e^2 - 22*e + 12, 12*e^3 - 2*e^2 - 46*e + 6, -11*e^2 + 6*e + 35, 4*e^3 - 20*e, 6*e^3 - 32*e + 6, -6*e^3 + 8*e^2 + 29*e - 15, -e^3 + e^2 - 4*e - 6, -4*e^3 + 2*e^2 + 16*e - 6, -6*e^3 + 2*e^2 + 32*e - 6, -7*e^3 + 5*e^2 + 16*e - 24, -4*e^3 + 10*e^2 + 30*e - 30, 5*e^3 + e^2 - 38*e - 6, -2*e^3 + 12*e + 2, 10*e^3 - 12*e^2 - 40*e + 38, 4*e^3 + 6*e^2 - 7*e - 25, -2*e^3 + 4*e + 8, 4*e^2 - 14*e - 22, 6*e^3 - 4*e^2 - 10*e + 20, -12*e^3 - 4*e^2 + 55*e + 17, -9*e^3 + 7*e^2 + 26*e - 30, -3*e^3 + 9*e^2 + 12*e - 24, -2*e^3 + 14*e^2 + 10*e - 36, 6*e^3 - 3*e^2 - 18*e + 23, 6*e^3 - e^2 - 30*e + 9, -8*e^3 - 8*e^2 + 24*e + 18, 4*e^3 - e + 15, -4*e^3 + 18*e - 22, 2*e^3 + 4*e^2 - 2*e - 4, -2*e^3 + 2*e^2 - e - 25, 7*e^3 + 3*e^2 - 28*e - 28, 2*e^3 + 6*e^2 - 3*e - 15, 10*e^3 + 10*e^2 - 42*e - 6, 4*e^3 + 7*e^2 - 10*e - 27, -6*e^3 + 7*e^2 + 32*e - 25, -6*e^3 - 8*e^2 + 30*e + 20, 11*e^3 + 3*e^2 - 54*e - 18, 5*e^3 + 5*e^2 - 18*e - 6, -6*e^3 - 12*e^2 + 22*e + 30, -2*e^3 + 8*e^2 - 4*e - 22, 4*e^2 + 10*e - 6, 2*e^3 - 4*e^2 - 12*e - 12, 4*e^3 - 16*e + 2, -5*e^3 + 15*e^2 + 28*e - 52, -4*e^3 - 6*e^2 + 6*e + 14, 2*e^3 - 6*e + 8, 12*e^3 + 8*e^2 - 39*e - 27, -11*e^3 + 5*e^2 + 48*e + 8, -e^3 - 7*e^2 + 6*e - 12, -12*e^3 + 7*e^2 + 50*e - 19, -2*e^3 + 2*e^2 - 11*e - 7, -8*e^3 - 18*e^2 + 26*e + 44, -4*e^3 + 2*e^2 + 21*e - 13, 4*e^3 - 3*e^2 - 6*e + 3, 4*e^3 + 6*e^2 + e - 25, -16*e^3 + 2*e^2 + 60*e + 14, 8*e^3 - 14*e^2 - 34*e + 30, 4*e^3 - 2*e^2 - 10*e - 12, -8*e^3 + 12*e^2 + 30*e - 54, 12*e^3 - 6*e^2 - 48*e + 18, 10*e^3 - 64*e - 10, -6*e^3 + 4*e^2 + 22*e - 10, 8*e^3 + 6*e^2 - 20*e - 22, 8*e^3 - 24*e + 18, -8*e^3 + 16*e^2 + 28*e - 52, 6*e^3 + 8*e^2 - 8*e - 34, -11*e^3 - 9*e^2 + 50*e + 8, -3*e^3 + 13*e^2 + 2*e - 58, 6*e^3 + 6*e^2 - 32*e - 6, 2*e^3 - 24*e^2 - 10*e + 68, -8*e^2 - e - 1, 4*e^3 - 4*e^2 - 28*e + 8, 8*e^2 - 4*e, 4*e^3 + 8*e^2 - 26*e + 6, 2*e^3 + 8*e^2 - 22*e - 28, -6*e^3 - 4*e^2 + 11*e + 9, -2*e^3 - 12*e^2 + 14*e + 36, -e^3 + e^2 + 20*e + 18, 8*e^3 - 4*e^2 - 47*e - 1, -e^3 - 25*e^2 + 4*e + 60, -16*e^3 - 10*e^2 + 56*e + 14, -8*e^3 - 10*e^2 + 32*e + 30, -8*e^3 + 2*e^2 + 20*e - 10, 7*e^3 + 3*e^2 - 22*e - 4, 6*e^3 + 2*e^2 - 30*e + 14, -12*e^3 - 10*e^2 + 44*e + 18, 8*e^3 - 5*e^2 - 38*e + 21, -4*e - 30, 16*e^3 + 8*e^2 - 52*e - 4, -14*e^3 + 8*e^2 + 54*e - 10, 14*e^3 + 6*e^2 - 35*e - 19]; 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;