Commit 9867426c authored by Gonzalo Tornaría's avatar Gonzalo Tornaría

fix a bug in galois_projection

parent 911c2d9d
......@@ -82,10 +82,12 @@ intrinsic galois_projection(R1 :: FldNum[FldRat],
// subgroup of gal2 corresponding to R1
gal_R1 := Stabilizer(gal2, {1,p});
assert #gal_R1 eq 2*#gal_R2;
if gal_R1 eq gal_R2 then
continue;
end if;
// subgroup of gal2 corresponding to R (Galois closure of R1)
gal_R := &meet Conjugates(gal2, gal_R1);
gal_R := Core(gal2, gal_R1);
// Check that {1, p} are really conjugates
if #gal2 eq #gal_R * #gal then
......@@ -93,6 +95,8 @@ intrinsic galois_projection(R1 :: FldNum[FldRat],
end if;
end for;
assert #gal_R1 eq 2*#gal_R2;
assert #gal2 eq #gal_R * #gal;
// proj : gal2 --> gal1
proj, gal1 := CosetAction(gal2, gal_R1);
......
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