I would like to collect some of your opinions.

The topics is mathematics, but the question is about using English language.

The context is the Introduction of a mathematics research paper.

I start: "We consider the Kirchhoff equation (1) u_tt ... [...]

Equation (1) is a quasi-linear integro-differential equation having a structure of an infinite-dimensional Hamiltonian system...

My questions:

1. What is better between "having" and "which has"? (I would like to write as plain as possible)

2. What is the correct form among the following six?

(Question about "the/a/--" and about "of an/of --")

having

__the__structure of

__an__infinite...

having

__a__structure of

__an__infinite...

having structure of

__an__infinite...

having

__the__structure of infinite...

having

__a__structure of infinite...

having structure of infinite...

3. Is it annoying to yours English ears the repeatition "

__Equation__(1) is a ...

__equation__"?

Thank you very much.

Salegrosso.