I know I have asked a similar question before but this time I have examples taken from COCA and they do puzzle me. I would love to hear explanations from native speakers.
The following (incomplete) sentences taken from COCA show three different ways of article usage before "reduction of something".
(1) $1.5 billion could be used for things like restoration of fish and wildlife, the reduction of mercury pollution and greenhouse gas reduction.
(2) Fasting imposes a reduction of calorie intake, which is particularly significant if the hours of darkness are few
(3) A key goal of the optimization phase is reduction of communication over-head via a range of techniques, including execution of communication in parallel
Can you say "a reduction of mercury pollution" instead of "the reduction of mercury pollution" in (1)? Likewise, can you say "the reduction of calorie intake" instead of "a reduction of calorie intake" in (2)? If you can, what difference in meaning would that make in each case?
My guess is that, in using "a", the speaker (or writer) has in mind some image of what is to be reduced, whereas in using "the", the speaker (or writer) has in mind more of the fact of reduction itself than what is to be reduced, lacking a better description.
Even if my guess is right, (3) still remains to be explained. Is the lack of article before "reduction of communications over-head" a case of ellipsis? If not, why don't you need an article here as in the other two examples? What difference does the absence of an article make in comparison with "the reduction of communication over-head" or "a reduction of (in) communication over-head"? Can you or should you use "a" or "the" in this case?
In addition, there is another issue in (1). There is no article in front of "restoration". Why is there no article here, whereas there is a definite article in front of "reduction"?