Zobrazeno 1 - 10
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pro vyhledávání: '"Suk-Geun Hwang"'
Autor:
Ki-Bong Nam, Suk-Geun Hwang
Publikováno v:
The American Mathematical Monthly. 127:269-272
A generalized Pythagorean theorem is an equation relating the squares of the volumes of faces of a particular k-simplex in n-dimensional Euclidean space. There are many proofs of this theorem. This...
Publikováno v:
International Journal of Mathematics and Mathematical Sciences, Vol 13, Iss 4, Pp 709-716 (1990)
Let Kn denote the set of all n×n nonnegative matrices with entry sum n. For X∈Kn with row sum vector (r1,…,rn), column sum vector (c1,…,cn), Let ϕ(X)=∏iri+∏jcj−perX. Dittert's conjecture asserts that ϕ(X)≤2−n!/nn for all X∈Kn wit
Externí odkaz:
https://doaj.org/article/42152867fda6443ab29041d7ad9d7bb5
Autor:
Ik-Pyo Kim, Suk-Geun Hwang
Publikováno v:
The College Mathematics Journal. 50:298-299
The cross product u→×v→ of vectors u→=[a1a2a3], v→=[b1b2b3] in the Euclidean 3-space is defined as follows (see [1, p. 138] or [3, p. 266]):Algebraic definition. u→×v→=[a2b3−a3b2−(a1b3−a3b1)a1b2−a2...
Publikováno v:
Linear Algebra and its Applications. 491:1-3
Autor:
Suk-Geun Hwang, Jin-Woo Park
Publikováno v:
Bulletin of the Korean Mathematical Society. 43:471-478
In this paper we prove that if AX=b is a partial sign-solvable linear system with A being sign non-singular matrix and if , then is a sign-solvable linear system, where denotes the submatrix of A occupying rows and columns in o and xo and be are subv
Autor:
Suk-Geun Hwang, Myung-Sook Cho
Publikováno v:
Bulletin of the Korean Mathematical Society. 43:343-352
A real matrix A is called a sign-central matrix if for, every matrix with the same sign pattern as A, the convex hull of columns of contains the zero vector. A sign-central matrix A is called a tight sign-central matrix if the Hadamard (entrywise) pr
Publikováno v:
Linear Algebra and its Applications. 407:296-310
A real matrix A is called sign-central if A ∼ x = 0 has a nonzero nonnegative solution x for every matrix A ∼ with the same sign pattern as A . A sign-central matrix A is called tight sign-central if the Hadamard(entrywise) product of any two col
Publikováno v:
Journal of the Korean Mathematical Society. 42:761-771
In this paper we present another characterization of (§1)-invariant sequences. We also introduce truncated Fibonacci and Lucas sequences of the second kind and show that a sequence x 2 R 1 is (i1)-invariant(1-invariant resp.) if and only if D £ 0
Autor:
Suk-Geun Hwang, Sung-Soo Pyo
Publikováno v:
Linear Algebra and its Applications. 379:77-83
For a positive integer n and for a real number s, let Γns denote the set of all n×n real matrices whose rows and columns have sum s. In this note, by an explicit constructive method, we prove the following. (i) Given any real n-tuple Λ=(λ1,λ2,
Autor:
Eun-Young Lee, Suk-Geun Hwang
Publikováno v:
Linear Algebra and its Applications. 376:97-108
For positive integers r, n with n⩾r+1, let Dr,n=OrJJIn, where Js denote the matrices of 1s of suitable sizes, and let Ω(Dr,n) denote the face of the polytope Ωr+n consisting of all (r+n)-square doubly stochastic matrices A such that A⩽Dr,n. In