For infringing a claim, all elements of a claim need to be infringed.
A claim a + b can either be “at least and b“ (typically) or “exactly a and b“ (for example exactly 40% sparkling water and 60% apple juice, very rare).
In your example, at least claim 1 must be “at least a and b“ because else a+b+c would not be a dependent claim as dependent claims are ...
Is it okay to use "optionally" in a claim?
No, for two reasons.
The purpose of an independent claim is to define the scope of the protection that you seek. Including an optional feature does not serve this aim (since you intend for it not to be a limitation on the scope), and so should not be included.
Moreover, it could unintentionally be an implicit ...
This is a great qestion!
Dependent claims are such a prominent thing and they don't give you anything in regards to claim scope. (Apart from interpretation maybe, but a well written description could get you there too.)
But let's look a little closer. (I'll be citing the epo manual because I know it better, but it's pretty close to the US thing)
An independent claim will always encompass all of its dependent claims. That means that something infringing a dependent claim will always infringe the independent claim too. A dependent claim is just a narrow version of the independent claim.
So let's imagine you would invalidate a dependent claim, e.g. a+b+c. Then your abc would still infringe the ...
If A is unknown, then a B that is A plus a regular thing "delta" is inherently unknown. So, a claim that says, "the thing of claim 1 where the bottom is red" is inherently novel if claim 1 is novel even though making the bottom red is not very interesting.
A dependent claim must always narrow down the scope of the associated independent claim.
Yes. That can even be used to determine the scope of the independent claim by analyzing how the dependent claim narrows it.
Hence, if someone infringes on a dependent claim, he will surely be infringing on the respective independent claim (it's like saying, if B is ...
First, a small note about terminology: the word "limitation" is almost a synonym for "feature."
To answer the questions, I'll come up with a simple example. Let's say your invention is a chair that levitates. You submit only three claims, and they read:
A chair comprising: a stool and at least three legs.
The chair of claim 1, further comprising a magnetic ...
No need to change status identifiers if any of the independent or dependent claims is unchanged. Status identifiers are needed to be changed in case of amendments (strikethrough of text, insertion of text, or dependency change) only.
You're right that a dependent claim is necessarily narrower than its associated independent claim. Nonetheless, there are benefits to dependent claims:
If the independent claim is not allowed, its narrower dependent claims may still survive.
Different claims are presumed to have different scope (doctrine of claims differentiation). Therefore, "fruit" in ...
You can't remove anything required by a referenced claim but you can add to it or you can narrow it. For example - The method of claim 1 where the hammer used in step b is a claw hammer. Or - the method of claim 1 where the dusting is accomplished with a feather.