4 papers
Prime-universal diagonal quadratic forms
Jangwon Ju, Daejun Kim, Kyoungmin Kim +2
A (positive definite and integral) quadratic form is said to be if it represents all primes. Recently, Doyle and Williams in [2] classified all prime-uni…
Representations of finite number of quadratic forms with same rank
Daejun Kim, Byeong-Kweon Oh
Let be positive integers with . Let be the largest integer such that for any (positive definite and integral) quadratic forms of rank $…
A sum of three nonunit squares of integers
Daejun Kim, Jeongwon Lee, Byeong-Kweon Oh
We say a positive integer is a sum of three nonunit squares if it is a sum of three squares of integers other than one. In this article, we find all integers which are sums of thre…
On a quadratic Waring's problem with congruence conditions
Daejun Kim
For each positive integer , let be the smallest positive integer such that every complete quadratic polynomial in variables which can be represented by a sum of…