The phrase 'dominant position over' is correct and usable in written English.
You can use it to refer to a situation in which someone or something has control or power over someone or something else. For example, "The dictator has maintained a dominant position over his people for years."
This was in a category that has long been dominated by Colgate, which had carefully built a dominant position over the last 80 years with few challengers.
The memorandum placed McMaster in a dominant position over the Homeland Security Council, giving him the power to determine the agenda for both bodies.
Complaints that Google prioritises its own services in manipulating search results, abusing its dominant position over 90% of the search market, started rumbling eight years ago and were formalised in 2009.
Regardless of whether the missteps of the first weeks of 2000 have cut in to his popularity, they have not affected Labor's dominant position over the Conservatives, who remain a party with sharp internal divisions and weak leadership.
He has been the president of the Confederation of African Football for two years longer than that, having maintained his dominant position over the continent's football administration for 27 years, since he was first elected in 1988.
European competition authorities are also increasingly looking at how companies like Facebook may hold a dominant position over people's digital information, which may give them an unfair advantage over rivals.
TMP Worldwide, largely because of its dominant position in recruiting over the Internet through its Monster.com site, has fared better than the other public search firms.
Perhaps that's why atheist attacks on religion end up looking a game of whack-a-mole: a belief pops up that looks like the key one and they come crashing down on it, only for another to pop up elsewhere, taking over the dominant position on the board.
Today, the mine-scape of Goa is being changed forever by Agarwal who is slowly but steadily taking over a dominant position there.
The changes from year to year in the herds converting to organic farming indicate that even though the SA infections might be dominated by a single dominant clone(s) at a given time, new clones may take over the dominant position in relative short time.
Antwerp was cut off from the sea; Amsterdam took over Antwerp's dominant position.
