/* 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![1, 0, -4, 0, 1]; F := NumberField(g); ZF := Integers(F); NN := ideal; primesArray := [ [2, 2, w^3 - 4*w + 1], [9, 3, -w^2 + 2], [23, 23, w^3 - w^2 - 4*w + 1], [23, 23, w^2 - w - 3], [23, 23, -w^2 - w + 3], [23, 23, -w^3 - w^2 + 4*w + 1], [25, 5, w^3 - 5*w + 1], [25, 5, w^3 - 5*w - 1], [47, 47, -3*w^3 + 2*w^2 + 12*w - 8], [47, 47, -2*w^3 - w^2 + 6*w], [47, 47, 2*w^3 - w^2 - 6*w], [47, 47, w^2 + w - 5], [49, 7, 2*w^3 - 6*w - 1], [49, 7, -2*w^3 + 6*w - 1], [71, 71, 2*w^3 - w^2 - 7*w + 1], [71, 71, 3*w^3 - w^2 - 11*w + 2], [71, 71, 4*w^3 - 2*w^2 - 14*w + 5], [71, 71, -3*w^3 + 2*w^2 + 10*w - 4], [73, 73, -w^3 - 2*w^2 + 3*w + 5], [73, 73, -w^3 + 2*w^2 + 3*w - 3], [73, 73, w^3 + 2*w^2 - 3*w - 3], [73, 73, w^3 - 2*w^2 - 3*w + 5], [97, 97, 2*w^2 + w - 4], [97, 97, w^3 + 2*w^2 - 4*w - 4], [97, 97, -w^3 + 2*w^2 + 4*w - 4], [97, 97, 2*w^2 - w - 4], [121, 11, 2*w^3 - 5*w], [121, 11, 3*w^3 - 10*w], [167, 167, -2*w^3 + 3*w^2 + 5*w - 7], [167, 167, -2*w^3 - w^2 + 10*w - 2], [167, 167, 3*w^3 - 11*w + 3], [167, 167, 3*w^3 - 2*w^2 - 10*w + 8], [169, 13, 2*w^3 - 9*w], [169, 13, w^3 - 6*w], [191, 191, w^2 - 2*w - 4], [191, 191, 2*w^3 + w^2 - 8*w], [191, 191, -2*w^3 + w^2 + 8*w], [191, 191, w^2 + 2*w - 4], [193, 193, -w - 4], [193, 193, -w^3 + 4*w - 4], [193, 193, w^3 - 4*w - 4], [193, 193, w - 4], [239, 239, 4*w^3 - 3*w^2 - 16*w + 12], [239, 239, -5*w^3 + w^2 + 19*w - 6], [239, 239, 4*w^3 - 16*w + 3], [239, 239, w^3 - 2*w^2 - 5*w + 9], [241, 241, 2*w^3 + w^2 - 10*w - 4], [241, 241, 2*w^3 - w^2 - 10*w], [241, 241, -2*w^3 - w^2 + 10*w], [241, 241, -2*w^3 + w^2 + 10*w - 4], [263, 263, -2*w^3 + 2*w^2 + 6*w - 7], [263, 263, -4*w^3 + 3*w^2 + 13*w - 9], [263, 263, -w^3 + 2*w^2 + 2*w - 6], [263, 263, -3*w^3 + 3*w^2 + 9*w - 8], [289, 17, 3*w^3 - 9*w + 1], [289, 17, -3*w^3 + 9*w + 1], [311, 311, 2*w^3 + w^2 - 8*w + 2], [311, 311, -w^2 - 2*w + 6], [311, 311, 3*w^3 - 2*w^2 - 13*w + 9], [311, 311, -2*w^3 + w^2 + 8*w + 2], [313, 313, -w^3 - w^2 + 4*w - 3], [313, 313, w^2 - w - 7], [313, 313, w^2 + w - 7], [313, 313, w^3 - w^2 - 4*w - 3], [337, 337, 3*w^3 - 8*w - 2], [337, 337, -4*w^3 + 13*w - 2], [337, 337, 4*w^3 - 13*w - 2], [337, 337, 3*w^3 - 8*w + 2], [359, 359, w^3 + 2*w^2 - 6*w - 6], [359, 359, -2*w^3 + 2*w^2 + 9*w - 2], [359, 359, 2*w^3 + 2*w^2 - 9*w - 2], [359, 359, -w^3 + 2*w^2 + 6*w - 6], [361, 19, -w^3 + 5*w - 5], [361, 19, w^3 - 5*w - 5], [383, 383, -w^3 + w^2 - 3], [383, 383, 4*w^3 + w^2 - 15*w - 1], [383, 383, -4*w^3 + w^2 + 15*w - 1], [383, 383, w^3 + w^2 - 3], [409, 409, 3*w^3 + w^2 - 8*w - 1], [409, 409, 4*w^3 - w^2 - 13*w + 3], [409, 409, 4*w^3 + w^2 - 13*w - 3], [409, 409, -3*w^3 + w^2 + 8*w - 1], [431, 431, -3*w^3 - 2*w^2 + 11*w + 3], [431, 431, -w^3 + 2*w^2 + w - 5], [431, 431, w^3 + 2*w^2 - w - 5], [431, 431, 3*w^3 - 2*w^2 - 11*w + 3], [433, 433, 3*w^3 - 13*w + 1], [433, 433, w^3 + w^2 - 4*w - 7], [433, 433, -w^3 + w^2 + 4*w - 7], [433, 433, 3*w^3 - 13*w - 1], [457, 457, 2*w^3 - 9*w - 6], [457, 457, w^3 - 6*w - 6], [457, 457, -w^3 + 6*w - 6], [457, 457, -2*w^3 + 9*w - 6], [479, 479, -2*w^3 + w^2 + 4*w - 4], [479, 479, 4*w^3 + w^2 - 14*w], [479, 479, -4*w^3 + w^2 + 14*w], [479, 479, 2*w^3 + w^2 - 4*w - 4], [503, 503, -3*w^3 - 2*w^2 + 10*w + 2], [503, 503, 2*w^3 + 2*w^2 - 5*w - 6], [503, 503, -2*w^3 + 2*w^2 + 5*w - 6], [503, 503, 3*w^3 - 2*w^2 - 10*w + 2], [577, 577, 3*w^3 + w^2 - 11*w - 8], [577, 577, -w^3 + w^2 + 6*w - 9], [577, 577, -4*w^3 + 4*w^2 + 15*w - 12], [577, 577, -4*w^3 + w^2 + 12*w], [599, 599, 2*w^3 + 2*w^2 - 8*w - 1], [599, 599, 2*w^2 - 2*w - 7], [599, 599, 2*w^2 + 2*w - 7], [599, 599, -2*w^3 + 2*w^2 + 8*w - 1], [601, 601, -w^3 + 3*w^2 + 4*w - 7], [601, 601, 3*w^2 - w - 5], [601, 601, 3*w^2 + w - 5], [601, 601, w^3 + 3*w^2 - 4*w - 7], [647, 647, -6*w^3 + 3*w^2 + 21*w - 7], [647, 647, -5*w^3 + 3*w^2 + 17*w - 6], [647, 647, 4*w^3 - 2*w^2 - 14*w + 3], [647, 647, 5*w^3 - 2*w^2 - 18*w + 4], [673, 673, -5*w^3 + 2*w^2 + 16*w - 6], [673, 673, 3*w^3 - w^2 - 14*w + 5], [673, 673, -3*w^3 - w^2 + 14*w + 5], [673, 673, 5*w^3 + 2*w^2 - 16*w - 6], [719, 719, 3*w^3 - w^2 - 13*w - 2], [719, 719, 6*w^3 - w^2 - 23*w + 7], [719, 719, -5*w^3 + 20*w - 4], [719, 719, -3*w^3 - w^2 + 13*w - 2], [743, 743, -3*w^3 + w^2 + 11*w + 2], [743, 743, w^3 + w^2 - w - 6], [743, 743, -w^3 + w^2 + w - 6], [743, 743, 3*w^3 + w^2 - 11*w + 2], [769, 769, -4*w^3 + 17*w - 2], [769, 769, -2*w^3 + w^2 + 8*w - 8], [769, 769, 2*w^3 + w^2 - 8*w - 8], [769, 769, 4*w^3 - 17*w - 2], [839, 839, w^3 + 3*w^2 - 6*w - 9], [839, 839, -4*w^3 - 2*w^2 + 16*w + 3], [839, 839, 4*w^3 - 2*w^2 - 16*w + 3], [839, 839, -w^3 + 3*w^2 + 6*w - 9], [841, 29, -4*w^3 + w^2 + 12*w - 2], [841, 29, 4*w^3 + w^2 - 12*w - 2], [863, 863, 2*w^2 + 3*w - 6], [863, 863, 3*w^3 - 2*w^2 - 12*w + 2], [863, 863, 3*w^3 + 2*w^2 - 12*w - 2], [863, 863, 2*w^2 - 3*w - 6], [887, 887, w^3 + 2*w^2 - 6*w - 8], [887, 887, 2*w^2 - 2*w - 9], [887, 887, 2*w^2 + 2*w - 9], [887, 887, -w^3 + 2*w^2 + 6*w - 8], [911, 911, -3*w^3 - 3*w^2 + 11*w + 4], [911, 911, w^3 + 3*w^2 - w - 8], [911, 911, -w^3 + 3*w^2 + w - 8], [911, 911, 3*w^3 - 3*w^2 - 11*w + 4], [937, 937, -w^3 - w^2 + 8*w + 1], [937, 937, 4*w^3 - w^2 - 17*w + 3], [937, 937, -4*w^3 - w^2 + 17*w + 3], [937, 937, w^3 - w^2 - 8*w + 1], [961, 31, -4*w^3 + 12*w - 1], [961, 31, 4*w^3 - 12*w - 1], [983, 983, w^2 + 3*w - 7], [983, 983, 3*w^3 - w^2 - 12*w - 3], [983, 983, 3*w^3 + w^2 - 12*w + 3], [983, 983, w^2 - 3*w - 7]]; primes := [ideal : I in primesArray]; heckePol := x^6 - 14*x^4 + 53*x^2 - 32; K := NumberField(heckePol); heckeEigenvaluesArray := [e, -e^4 + 7*e^2 - 2, -2*e, 1/2*e^5 - 9/2*e^3 + 8*e, -2*e, 1/2*e^5 - 9/2*e^3 + 8*e, 1/2*e^4 - 9/2*e^2 + 6, 1/2*e^4 - 9/2*e^2 + 6, 1/2*e^5 - 9/2*e^3 + 6*e, -e^5 + 9*e^3 - 14*e, 1/2*e^5 - 9/2*e^3 + 6*e, -e^5 + 9*e^3 - 14*e, -e^4 + 11*e^2 - 18, -1, 2*e^3 - 14*e, -2*e^3 + 12*e, 2*e^3 - 14*e, -2*e^3 + 12*e, -2*e^2 + 2, -2*e^2 + 2, -e^4 + 7*e^2 + 2, -e^4 + 7*e^2 + 2, -1/2*e^4 + 5/2*e^2 + 6, 3*e^4 - 23*e^2 + 22, -1/2*e^4 + 5/2*e^2 + 6, 3*e^4 - 23*e^2 + 22, 2*e^4 - 16*e^2 + 14, 2*e^4 - 16*e^2 + 14, -e^5 + 5*e^3 + 12*e, -3/2*e^5 + 27/2*e^3 - 24*e, -e^5 + 5*e^3 + 12*e, -3/2*e^5 + 27/2*e^3 - 24*e, 3/2*e^4 - 27/2*e^2 + 10, 3/2*e^4 - 27/2*e^2 + 10, -e^5 + 9*e^3 - 16*e, -e^5 + 9*e^3 - 16*e, -e^5 + 7*e^3 + 2*e, -e^5 + 7*e^3 + 2*e, -7/2*e^4 + 59/2*e^2 - 38, -7/2*e^4 + 59/2*e^2 - 38, 5/2*e^4 - 41/2*e^2 + 26, 5/2*e^4 - 41/2*e^2 + 26, -1/2*e^5 + 1/2*e^3 + 26*e, -1/2*e^5 + 1/2*e^3 + 26*e, e^5 - 5*e^3 - 16*e, e^5 - 5*e^3 - 16*e, 4*e^4 - 32*e^2 + 26, 1/2*e^4 - 13/2*e^2 + 10, 4*e^4 - 32*e^2 + 26, 1/2*e^4 - 13/2*e^2 + 10, -e^5 + 15*e^3 - 46*e, -e^5 + 15*e^3 - 46*e, -e^5 + 9*e^3 - 12*e, -e^5 + 9*e^3 - 12*e, -4*e^4 + 28*e^2 + 2, e^4 + e^2 - 30, 4*e^3 - 22*e, e^5 - 7*e^3 + 6*e, 4*e^3 - 22*e, e^5 - 7*e^3 + 6*e, -5/2*e^4 + 45/2*e^2 - 26, -5/2*e^4 + 45/2*e^2 - 26, -2*e^4 + 14*e^2 - 10, -2*e^4 + 14*e^2 - 10, -e^4 + 13*e^2 - 18, -4*e^2 + 14, -e^4 + 13*e^2 - 18, -4*e^2 + 14, -e^5 + 5*e^3 + 6*e, 3/2*e^5 - 27/2*e^3 + 20*e, -e^5 + 5*e^3 + 6*e, 3/2*e^5 - 27/2*e^3 + 20*e, 2*e^4 - 12*e^2 - 2, 2*e^4 - 12*e^2 - 2, 3/2*e^5 - 27/2*e^3 + 18*e, 3/2*e^5 - 27/2*e^3 + 18*e, e^5 - 11*e^3 + 26*e, e^5 - 11*e^3 + 26*e, 1/2*e^4 - 1/2*e^2 - 6, 1/2*e^4 - 1/2*e^2 - 6, e^4 - 9*e^2 + 10, e^4 - 9*e^2 + 10, -1/2*e^5 + 1/2*e^3 + 30*e, -1/2*e^5 + 1/2*e^3 + 30*e, -4*e^3 + 20*e, -4*e^3 + 20*e, -2*e^4 + 18*e^2 - 26, -2*e^4 + 18*e^2 - 26, 3/2*e^4 - 15/2*e^2 - 10, 3/2*e^4 - 15/2*e^2 - 10, -3/2*e^4 + 27/2*e^2 - 22, -3/2*e^4 + 27/2*e^2 - 22, -3/2*e^4 + 27/2*e^2 - 22, -3/2*e^4 + 27/2*e^2 - 22, 1/2*e^5 + 7/2*e^3 - 42*e, 1/2*e^5 + 7/2*e^3 - 42*e, -e^5 + 15*e^3 - 54*e, -e^5 + 15*e^3 - 54*e, -4*e^3 + 34*e, e^5 - 15*e^3 + 42*e, -4*e^3 + 34*e, e^5 - 15*e^3 + 42*e, 3*e^4 - 33*e^2 + 62, 8*e^2 - 34, 3*e^4 - 33*e^2 + 62, 8*e^2 - 34, 3*e^5 - 27*e^3 + 40*e, 3*e^5 - 27*e^3 + 40*e, -2*e^3 - 2*e, -2*e^3 - 2*e, -2*e^4 + 14*e^2 + 18, 3*e^4 - 21*e^2 + 18, -2*e^4 + 14*e^2 + 18, 3*e^4 - 21*e^2 + 18, -3/2*e^5 + 35/2*e^3 - 60*e, 2*e^5 - 16*e^3 + 8*e, -3/2*e^5 + 35/2*e^3 - 60*e, 2*e^5 - 16*e^3 + 8*e, 5*e^4 - 37*e^2 + 22, 5*e^4 - 37*e^2 + 22, -3*e^4 + 31*e^2 - 42, -3*e^4 + 31*e^2 - 42, 3*e^5 - 31*e^3 + 66*e, 3*e^5 - 31*e^3 + 66*e, -5/2*e^5 + 37/2*e^3 - 14*e, -5/2*e^5 + 37/2*e^3 - 14*e, -2*e^5 + 18*e^3 - 22*e, -2*e^5 + 18*e^3 - 22*e, 1/2*e^5 + 7/2*e^3 - 44*e, 1/2*e^5 + 7/2*e^3 - 44*e, -5*e^4 + 41*e^2 - 54, -7/2*e^4 + 67/2*e^2 - 38, -5*e^4 + 41*e^2 - 54, -7/2*e^4 + 67/2*e^2 - 38, -e^5 + 5*e^3 + 16*e, -1/2*e^5 + 17/2*e^3 - 36*e, -e^5 + 5*e^3 + 16*e, -1/2*e^5 + 17/2*e^3 - 36*e, e^4 - 13*e^2 + 38, e^4 - 13*e^2 + 38, -3*e^5 + 27*e^3 - 42*e, -3*e^5 + 27*e^3 - 42*e, 2*e^5 - 22*e^3 + 64*e, 2*e^5 - 22*e^3 + 64*e, 5/2*e^5 - 53/2*e^3 + 52*e, -2*e^3 + 24*e, 5/2*e^5 - 53/2*e^3 + 52*e, -2*e^3 + 24*e, 2*e^5 - 22*e^3 + 60*e, 5/2*e^5 - 53/2*e^3 + 50*e, 2*e^5 - 22*e^3 + 60*e, 5/2*e^5 - 53/2*e^3 + 50*e, -6*e^2 + 62, -2*e^4 + 10*e^2 + 30, -6*e^2 + 62, -2*e^4 + 10*e^2 + 30, -4*e^4 + 32*e^2 - 2, -4*e^4 + 32*e^2 - 2, e^5 - 13*e^3 + 44*e, e^5 - 13*e^3 + 44*e, 1/2*e^5 - 9/2*e^3 + 28*e, 1/2*e^5 - 9/2*e^3 + 28*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;