The concept that the claims defining an invention in a patent application must not be a predictable improvement on what has been done or published before the priority date.
The concept that the claims defining an invention in a patent application must involve an inventive step if, when compared with what is already known (i.e. prior art), it would not be obvious to someone skilled in the art.
If the invention could readily be deduced at the time the invention was made from publicly available information ( prior art) by a person of ordinary skill in that art, it is obvious. Prior art may be combined to show that an invention would have been obvious. (For example, the teachings of two or more prior art patents or a prior art patent and a prior art article may be combined). If an invention would have been obvious to a person of ordinary skill in the art at the time the invention was made, then it is not patentable.
The claimed inventive step is trivial and would not be deemed significant by someone 'skilled in the art' (an expert in that field).
If an individual skilled in the prior art finds the subject matter to be obvious based on the prior art itself, the claim or claims of the application may be rejected based on the fact that it is obvious.