The author sharpens a result of Jia and Liu (2000), showing that for sufficiently large \ (x \), the interval \ (x, x+x^1{2+} \) contains an integer with a prime factor larger than \ (x^51{53-} \). This gives a solution with \ (= 253 \) to the Exercise 5. 1 in Harman's monograph.
Runbo Li (Thu,) studied this question.