$AE = [Ä {A \u0308}]; $OE = [Ö {O \u0308}]; $UE = [Ü {U \u0308}]; [ä {a \u0308}] → ae; [ö {o \u0308}] → oe; [ü {u \u0308}] → ue; {$AE} [:Lowercase:] → Ae; {$OE} [:Lowercase:] → Oe; {$UE} [:Lowercase:] → Ue; $AE → AE; $OE → OE; $UE → UE; ::Any-ASCII;