Since my country does not impose restrictions on patent applications, but only limits patent authorization, no matter what kind of invention, you can apply for a patent, even if it has been applied for by someone else. However, in this case, the patent will generally not be authorized because the patent applied for by others has lost its novelty. Even in some cases, such as utility models, which are directly authorized without conducting a search, the right is unstable and very likely to be granted. It is easy to be invalidated in the post-authorization process and regarded as not existing from the beginning.
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