In Europe , with its stuffy, literary, and sanctimonious bragging style of patent claims, characterized by refers to the point of innovation. Here in US we claim the aspect of invention by using having or featuring.
Again, first time you mention something it is always a, otherwise an examiner will return a no antecedent basis response.
Consider a dependent claim: Anything introduced there in the preamble is henceforth (in the claim or independent) the. Anything introduced after the preamble is said.
Identification is a noun. Identifying is a verb. Steps in a method claim are verbs.
