"arguably by" is correct and usable in written English.
It is used to indicate that what follows is open to debate. For example, "The most influential artist of the 20th century was arguably Pablo Picasso."
Arguably by one measure – guns – yes.
Arguably, by the end of 2015, the fashion heat has gone from the shoe.
All 64 items in this "Musical Song-book" have accompaniments written by Bach, and these five works are arguably by the great man too.
Arguably, by this stage Hemingway is too drunk, depressive and irascible to convince any of his new conquests to marry him.
(In Australia's case the impact on saving is not clear cut: the saving rate has fallen nonetheless, though arguably by less than it would have done without the mandatory component).
This has a big effect on interstate commerce, though arguably by similar logic one might oblige people to buy gym memberships or broccoli.On a sticky wicketThese arguments were distilled in the lower courts long ago.
Paris' new street cred is arguably led by Vetements, founded by Demna Gvasalia and collective in 2014.
Our own garments are not even unique, being inspired by ancient Jewish ceremonies and arguably influenced by Masonic symbols.
As mentioned above this is arguably implied by the conjunction of (3) and (4), and also by (5).
In the 2000s, emboldened by their predecessors, a new generation of Asian-American rappers emerged, arguably helmed by Chinese-American MC Jin and Korean-American Dumbfoundead.
The Zwicker count was dropped by the full Senate on the grounds that McCarthy's conduct was arguably "induced" by Zwicker's own behavior.
