<<< native [ EOver False (EIdentifier "x") (ESymbol Accent "\168") , ESymbol Rel "\8800" , EOver False (EIdentifier "x") (ESymbol Ord "\168") , ESymbol Rel "=" , EOver False (EIdentifier "x") (ESymbol Ord "\168") , ESymbol Rel "=" , EOver False (EIdentifier "x") (ESymbol Ord "\168") ] >>> mml $$\ddot{x}\ne \ddot{x}=\ddot{x}=\ddot{x}$$