Yazar "Yagci, Melek" seçeneğine göre listele

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  • Küçük Resim
    Öğe
    On isolated subsemigroups of order-decreasing transformation semigroups
    (Hacettepe Univ, Fac Sci, 2026) Yagci, Melek; Ayik, Hayrullah
    For n E N, let Dn be the semigroup of all order-decrasing transformations on Xn = {1, ... , n}, under its natural order. In this paper, we determine isolated, completely isolated, and (left/right) convex subsemigroups of Dn. Furthermore, for {1} =6 U C Xn which contains 1, we find the rank of Dn[U] = {cx E Dn : U C Xn} which is a convex subsemigroup of Dn.
  • [ X ]
    Öğe
    On Nilpotent Subsemigroups of the Order-Decreasing Transformation Semigroups
    (Springernature, 2023) Yagci, Melek
    For n is an element of N, let D-n be the semigroup of all order-decreasing transformations on X-n = {1, ... , n}, under its natural order, and let E(D-n) be the set of all idempotents in D-n and for any xi is an element of E(D-n), let D-n(xi) = {alpha e D-n : alpha(m) = xi for some m is an element of Z(+)}. In this paper, first we show that D-n(xi) is the maximum nilpotent subsemigroup of D-n with zero element xi. Moreover, we determine the minimum generating set of D-n(xi), and so the rank of D-n(xi). Also, we find the cardinality of D-n(xi).