toTseitinEncode (Not e1) =
    let a1 = newRef [1]
        in foldAnd( [Not a1] ++ (toTseitinEncode' [1] e1))
toTseitinEncode (Not e1) =
    let a1 = newRef [1]
        in foldAnd( [Not a1] ++ (toTseitinEncode' [1] e1))
toTseitinEncode (Not e1) =
    let a1 = newRef [1]
        in foldAnd( [Not a1] ++ (toTseitinEncode' [1] e1))