Czechoslovak Mathematical Journal

, Volume 56, Issue 4, pp 1085–1108 | Cite as

On left C-U-liberal semigroups

  • Yong He
  • Fang Shao
  • Shi-qun Li
  • Wei Gao


In this paper the equivalence \(\tilde {\cal Q}^U \) on a semigroup S in terms of a set U of idempotents in S is defined. A semigroup S is called a U-liberal semigroup with U as the set of projections and denoted by S(U) if every \(\tilde {\cal Q}^U \)-class in it contains an element in U. A class of U-liberal semigroups is characterized and some special cases are considered.


equivalence \(\tilde {\cal Q}^U \) left C-U-liberal semigroup left semi-spined product band-formal construction left C-liberal semigroup 


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Copyright information

© Mathematical Institute, Academy of Sciences of Czech Republic 2006

Authors and Affiliations

  • Yong He
    • 1
  • Fang Shao
    • 2
  • Shi-qun Li
    • 3
  • Wei Gao
    • 4
  1. 1.School of ComputerHunan University of Science & TechnologyXiangtan, HunanP. R. China
  2. 2.Department of Scientific ReserchHunan University of Science & TechnologyXiangtan, HunanP. R. China
  3. 3.School of MathematicsHunan University of Science & TechnologyXiangtan, HunanP. R. China
  4. 4.Department and Institute of MathematicsFudan universityShanghaiP. R. China

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