• 제목/요약/키워드: linear maps

검색결과 211건 처리시간 0.02초

THE NEARLY ADDITIVE MAPS

  • Ansari-Piri, Esmaeeil;Eghbali, Nasrin
    • 대한수학회보
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    • 제46권2호
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    • pp.199-207
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    • 2009
  • This note is a verification on the relations between almost linear and nearly additive maps; and the continuity of almost multiplicative nearly additive maps. Also we consider the stability of nearly additive and almost linear maps.

BOUNDARIES OF THE CONE OF POSITIVE LINEAR MAPS AND ITS SUBCONES IN MATRIX ALGEBRAS

  • Kye, Seung-Hyeok
    • 대한수학회지
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    • 제33권3호
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    • pp.669-677
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    • 1996
  • Let $M_n$ be the $C^*$-algebra of all $n \times n$ matrices over the complex field, and $P[M_m, M_n]$ the convex cone of all positive linear maps from $M_m$ into $M_n$ that is, the maps which send the set of positive semidefinite matrices in $M_m$ into the set of positive semi-definite matrices in $M_n$. The convex structures of $P[M_m, M_n]$ are highly complicated even in low dimensions, and several authors [CL, KK, LW, O, R, S, W]have considered the possibility of decomposition of $P[M_m, M_n] into subcones.

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INTERSECTIONS OF MAXIMAL FACES IN THE CONVEX SET OF POSITIVE LINEAR MAPS BETWEEN MATRIX ALGEBRAS

  • Kye, Seung-Hyeok;Lee, Sa-Ge
    • 대한수학회논문집
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    • 제10권4호
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    • pp.917-924
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    • 1995
  • Let $P_I$ be the convex compact set of all unital positive linear maps between the $n \times n$ matrix algebra over the complex field. We find a necessary and sufficient condition for which two maximal faces of $\cap P_I$ intersect. In particular, we show that any pair of maximal faces of $P_I$ has the nonempty intersection, whenever $n \geq 3$.

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INJECTIVE LINEAR MAPS ON τ(F) THAT PRESERVE THE ADDITIVITY OF RANK

  • Slowik, Roksana
    • 대한수학회보
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    • 제54권1호
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    • pp.277-287
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    • 2017
  • We consider ${\tau}_{\infty}(F)$ - the space of upper triangular infinite matrices over a field F. We investigate injective linear maps on this space which preserve the additivity of rank, i.e., the maps ${\phi}$ such that rank(x + y) = rank(x) + rank(y) implies rank(${\phi}(x+y)$) = rank(${\phi}(x)$) + rank(${\phi}(y)$) for all $x,\;y{\in}{\tau}_{\infty}(F)$.

COMMON FIXED POINT THEOREM AND INVARIANT APPROXIMATION IN COMPLETE LINEAR METRIC SPACES

  • Nashine, Hemant Kumar
    • East Asian mathematical journal
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    • 제28권5호
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    • pp.533-541
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    • 2012
  • A common fixed point result of Gregus type for subcompatible mappings defined on a complete linear metric space is obtained. The considered underlying space is generalized from Banach space to complete linear metric spaces, which include Banach space and complete metrizable locally convex spaces. Invariant approximation results have also been determined as its application.