当且仅当

On this basis, we give the characterization of the compact set in E〓,τ

引入了模糊数网的最终等度左连续概念，利用它得到了模糊数序列在水平收敛意义下存在极限的一个充要条件，在此基础上给出了空间E〓，τ(l中紧集的特征刻画，即空间E〓，τ(l中的闭集U是紧的当且仅当U一致支集有界，且U的每个网有在（0，1上最终等度左连续、在λ=0处最终等度右连续的子网。

Let C be a nonempty closed convex subset of a Hilbert space H, P:H→C be a nearest point projection, and T:C→H be a nonexpansive mapping satisfying the weakly inwardness condition, and :C→C be a fixed contractive mapping. Let the implicit iterative sequences {x},{y} and the explicit iterative sequences {x},{y}.

设C为实Hilbert空间H的非空闭凸子集，P：H→C为最近点投影映射，T：C→H为非扩张映象，且T满足弱内向条件，：C→C为压缩映象。t∈(0，l)，定义了2种隐式粘性迭代序列{x}，{y}和2种显式粘性迭代序列{x}，{y}，证明了T有不动点当且仅当序列{x}，{y}，{x}，{y}有界。

Let be a homeomorphism, the following statements were obtained: if is distal and has POTP ,then does not have the average shadowing property; if is equicontinuous and has the average shadowing property, then f is minimal; let :X→X be distal and chaintransitive, then does not have POTP; is distal if and only if is distal.

设是个同胚映射，得到了如下结果：若有POTP且是distal的，则不具有平均跟踪性；若有平均跟踪性且是等度连续的，则是极小的；若是distal的且是链可迁的，则不具有POTP；是distal的当且仅当是distal的。

Results Two new characterizations of regular rings are given.(1) If R is a left SF'-ring and R/Z is reduced, then R is strongly regular;(2) R is strongly regular if and only if R is a left SF'-ring whose every idempotent element of R is left semi-center and is LANE-ring.

结果 得到了SF'-环是强正则环的两个充要条件：(1)R是左SF'-环，如果R/Z是约化的，则R是强正则环；(2)R是强正则环当且仅当R是满足幂等元左半中心的左SF'-环，且R是LANE-环。

In addition, we obtain the following results:(1) A ring R is weakly unit-regular if and only if so is the n×n matrix ring Mn of R for any n≥1;(2) Let R be a ring such that R/J is regular.

另外，我们还证明了下面两个结果：(1)环R是弱幺正则的当且仅当Mn(n≥1)是弱幺正则环；(2)假设R是一个环且使得R/J是正则环。

A general ring I is a clean general ring if and only if its power series ring is a clean general ring if and only if its skew power series ring is a clean general ring.

1一般环I是一般clean环当且仅当I的形式幂级数环是一般clean环当且仅当I的斜幂级数环是一般clean环。

In Particular, we prove that N is the equality relation on S if and only if S is a semilattice and N is the universal relation on S if and only if 5 is the only principal filter.

其次，证明了N是偏序半群S中的恒等关系当且仅当S是一个半格，N是偏序半群S中的泛关系当且仅当S自身是S中唯一的主滤子。

Ureg such that =; E (the ideal extension of a ring R by its ideal I) is an exchange ring if and only if R and I are both exchange.

一个一般环I是exchange的当且仅当对它的任意理想L以及=2∈I/L，存在w∈r.ureg使得=；E(环R通过它的理想I生成的理想扩张)是一个exchange环当且仅当R和I都是exchange环。

As applications, we prove the following results: If / has pointwise pseudo-orbit tracing property, for any k ∈ Z+, and fk is chain transitive, then for any k ∈ Z+, fk has open set transitive ; If f has pointwise pseudo-orbit tracing property, and for any n ∈ Z+,fn is chain transitive, then f has sensitive dependence on initial conditions; If f is open set mixing and has pointwise pseudo-orbit tracing property, then f has property P; Let f :→ be a homeomophism, then f is pointwise pseudo-orbit tracing property if and only if the shift map σf is pointwise pseudo-orbit tracing property.

作为应用，证明如下结论：若f具有逐点伪轨跟踪性质，且对任意k∈Z+，fk为链转换的，那么对任意k∈Z+，fk为开集转换；若f具有逐点伪轨跟踪性质，且对任意n∈Z+，fn为链转换的，则f具有初始敏感依赖性质；若f为开集混合的，且具有逐点伪轨跟踪性质，那么f具有性质P；设f：→是同胚映射，那么f具有逐点伪轨跟踪性质当且仅当移位映射σf具有逐点伪轨跟踪性质。

It is shown that a radical square zero algebra is wild if and only if it is of Corner's type, and it is strictly wild if and only if it is endo-wild. This gives a negative answer to a problem posed by Simson.

此外，证明了根方零代数是野的当且仅当它具有Corner型；是严格野的当且仅当它是Endo-wild的，从而给出Simson问题的否定回答。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。