The phrase "assertion in writing" is correct and usable in written English.
It can be used when referring to a statement or claim that is documented or formally expressed in written form.
Example: "The lawyer submitted an assertion in writing to support her client's case."
Alternatives: "written statement" or "documented claim".
"Colting's assertion that his purpose in writing Catcher was to 'critically examin[e] the character Holden, and his presentation in Catcher as an authentic and admirable (maybe even heroic) figure' is problematic and lacking in credibility," Batts said in her ruling.
Mr. Yoo denied assertions by some officials that he had sought to bypass Mr. Ashcroft in writing the 2002 memorandum and other opinions favored by the White House.
("Reality, in Trecartin's multi-racial social bubble, derives from personality assertion," as Wayne Koestenbaum wrote in Artforum).
Zamalek president Mortada Mansour, a larger than life figure, whose at times comical outbursts often persuade the government to maintain a distance even though they support Mr. Al Sisi's policies, charged that Al Ahli's victory on the pitch was due to "ghosts and jinns" and that his assertions are "written in the holy Quran".
In Programatica, predicate definitions and property assertions written in P-logic, a programming logic for Haskell, can be embedded in the text of a Haskell program module.
Schematron rules are assertion tests written using XPath syntax.
The administration would make an assertion, people would make an assertion, people would write it down as if it were true, and put it in the newspaper or on television.
Is "our culture" a "limbo of arbitrary choices and gratuitous assertions," as Kramer wrote in 1972?
Contrary to the assertions of French authors writing in the colonial period, Duong did not seek the imposition of a French protectorate over his country.
