I would like to get a better understanding on how infringement is determined in case of combined claims. Specifically I am confronted with a pending patent combining methods A and B in the following wording I abstracted out of the claims document:

  1. A method for [goal], [hardware], the method comprising steps of [hardware operation], doing [subgoal1] by [method type], wherein [A] is used as [method type] for [subgoal1] that has property [a], doing [subgoal2], wherein [subgoal2] is done by [B], [subgoal3], output the result.

  2. The method for [goal] according to claim 1, characterized in that in the step of [subgoal1], [A] is used as [method type].


  1. A system for [goal], [hardware], [more detail of hardware], configured to [copy of wording of claim 1 from [hardware operation] to the end].

Important thing here is that neither A nor B is novel. Also the hardware setup is nothing special. The combination of A and B is IMO obvious but that may be debatable. Same for the application idea, i.e. to use it for [goal]. The only novel thing is the insight that B is workable on top of A at all due to property [a]. In any case, only the combination [goal], A and B can be patentable then I suspect...? There is prior work (?) in form of a master thesis, since years ago disclosed at arxiv, using A and C to achieve [goal], yes precisely the same [goal] as in claim 1. However, C is overly complex because it does not exploit property [a] specifically. I suspect the inventors are not aware of that document as they did not cite it. There is various further work using A and X to achieve [other type of goal, yet in the same application field], none of it cited by the patent. This makes me think that claim 2 is highly questionable.

First question: Would "A and C to achieve [goal]" form prior art for claim 2? Am I right in thinking that it would not form prior art for claim 1 because C is replaced with B?

Second question: I researched a method doing A and D, where D requires property . If I ever decided to use this method beyond research and teaching, would that infringe claim 1?

I think it would likely infringe claim 2, which is why I am curious whether claim 2 could be invalidated due to prior art "A and C to achieve [goal]".

Third question: Would a method doing A and D infringe claim 2?

I also researched a method [A2] that would also yield property [a]. Assuming that [A2] is sufficiently distinct from [A] such that it would not violate claim 2 on its own, would the approach "A2 and D" infringe claim 1? More provocatively, would "A2 and B" infringe claim 1? I.e., how protective is the hint on property [a] in claim 1, especially given that neither A nor the knowledge that it has property [a] is novel?

Fourth question: Claim 8 seems to do nothing else than protecting it as a system in addition to claim 1 which protects it as a method. How would this affect answers to my previous questions?

I know that a safe answer requires consulting a patent attorney and can easily cost thousands of euros. I aim to understand and confirm as much as possible by myself with the goal to either make the consultation as efficient as possible or to submit a third party objection on my own.

If an answer requires further detail, what detail would be important? Basically I appreciate every hint, partial answer, etc.

The pending patent is filed in US and Europe. I am more interested in the Europe case if answers would much depend on this distinction. However also US-answers are welcome of course.

  • If the application has published, please specify it. In any case, claims in applications are often wildly broad often far narrower if granted.
    – Eric S
    Mar 21, 2019 at 14:41
  • I had some correspondence with the inventors and if one of them happens to read this they could probably easily guess my identity. I would prefer to keep it anonymous at this stage. Especially as the answers now imply that my method would likely not be an infringement at all.
    – F. Xen
    Apr 4, 2019 at 22:18

2 Answers 2


First question - Can a reference with A and C keep a claim for A and B from being patented?

Maybe - To be patentable a claim needs to be novel and non-obvious. Novelty is easy. If it is different from anything ever disclosed in a single embodiment of a system in a single document it is novel. A and B is novel over A and C. Obviousness is more complicated. Prior art that involved A and C does not create any problem with the novelty of A and B. A and B might be obvious if A and C has been done in light of something that says B is a good substitute for C under the circumstances. Note, claim 1 and 2 are very similar. The only difference is something that infringes 1 only also infringes 2 if A is done in a specific way.

Second and third questions - Can doing A and D infringe claim 1 or 2?

No - To infringe a method claim all of the steps in a claim must be performed. So, for example, if the claims require the actions A and B and you perform A and D (but not B), you would not literally infringe. Again The analysis is the same for all of the claims you list.

Fourth question - As another person answered, a system claim is infringed by a system sitting in a box on a shelf. A method claim requires the system to be powered up and engaged in action. Covering both circumstances is prudent.


Claim 2 cannot be infringed if claim 1 is not infringed. Same for invalidation. Dependent claims incorporate all elements of the claims they depend on.

It's usual to have a system claim to be able to stop products before they are used which can sometimes be hard with a method claim. (Oversimplified: A method claim is not infringed until the method is actually practiced. // with a few exceptions).

  • I'll leave the detailed answer to someone else or to another day, but this should get you started.
    – user18033
    Mar 21, 2019 at 18:17
  • It seems like I totally misunderstood the meaning of claim 2. I thought it would exists to protect the submethod on its own. (So, I guess its purpose is to make a more detailed infringement more expensive.) Thanks for clarifying!
    – F. Xen
    Apr 4, 2019 at 22:14

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