handles zero ideal input

Author: ederc

src/algorithms/groebner-bases.jl

@@ -131,10 +131,16 @@ function _core_groebner_basis(
 
     F = I.gens
     R = first(F).parent
+    if F == [R(0)]
+        return F
+    end
     nr_vars     = nvars(R)
     nr_gens     = length(F)
     field_char  = Int(characteristic(R))
 
+    println(field_char)
+    println(I)
+
     mon_order       = 0
     elim_block_size = eliminate
     reduce_gb       = Int(complete_reduction)

src/algorithms/normal-forms.jl

@@ -121,10 +121,18 @@ function _core_normal_form(
 
     #= first get a degree reverse lexicographical Gröbner basis for I =#
     if !haskey(I.gb, 0)
-        groebner_basis(I, eliminate = 0, la_option = 44, info_level = info_level)
+        if field_char > 2^17
+            groebner_basis(I, eliminate = 0, la_option = 44, info_level = info_level)
+        else
+            groebner_basis(I, eliminate = 0, la_option = 2, info_level = info_level)
+        end
     end
     G = I.gb[0]
 
+    if G == [R(0)]
+        return F
+    end
+
     tbr_nr_gens = length(F)
     bs_nr_gens  = length(G)
     is_gb       = 1