2 citations · 2 across the 8 of their papers we have counts for
8 papers
On the finiteness of Carmichael numbers with Fermat factors and
Yu Tsumura
Let be a Carmichael number and let be the least common multiple of , where runs over the prime factors of . We determine all the Carmichael numbers with a F…
A 2-categorical extension of the Reshetikhin-Turaev theory
Yu Tsumura
We concretely construct a 2-categorically extended TQFT that extends the Reshetikhin-Turaev TQFT to cobordisms with corners. The source category will be a well chosen 2-category of…
On compositeness of special types of integers
Yu Tsumura
In paper on a classification of Lehmer triples, Juricevic conjectured that there are infinitely many primes of special form. We disprove one of his conjectures and consider the oth…
The number of points on an elliptic curve with square x-coordinates
Yu Tsumura
Let K be a finite field. We know that a half of elements of K* is a square. So it is natural to ask how many of them appear as x-coordinate of points on an elliptic curve over K. W…
The quadratic character of 1+\sqrt{2} and an elliptic curve
Yu Tsumura
When p is congruent to 1 mod 8, we have a criterion of the quadratic character of 1+\sqrt{2}, which is related to the class number of \Q(\sqrt{-p}). In this paper, we obtain a simi…
Additive properties of even perfect numbers
Yu Tsumura
A positive integer n is said to be perfect if sigma(n)=2n, where sigma denotes the sum of the divisors of n. In this article, we show that if n is an even perfect number, then any…