当且仅当

Two quasigroups are ''' isotopic ''' if there is an isotopy between them.

两个拟群是'''合伦'''的当且仅当它们之间存在合伦映射。

Moreover, it is obtained that, if X is a core compact and locally connected space, then the Isbell and Scott topologies agree on functions space for all continuous L-Domain L with a least element if and only if X is an RW-space.

而且还证明了，若X是核紧的局部连通空间，则对所有有最小元的连续L-DomainL，上的Isbell拓扑和Scott拓扑相同当且仅当X是RW-空间。

Beginning a conditional-assembly block with the line %ifdef MACRO will assemble the subsequent code if, and only if, a single-line macro called MACRO is defined.

以代码行%ifdef MACRO开头的条件汇编块将汇编接着下来的代码当且仅当叫做MACRO的单行宏被定义的情况下。

By the definition of Green-relation and the analogue of generalized Greens lemma, this paper first studied some properties of H-class、 D--class of rpp semigroups, then by left S-system 、-bisystem and tensor product, we described a blocked Rees matrix semigroup. Especially, the paper studied primitive rpp semigroups .

本文利用在rpp半群上定义的广义Green~(l-关系及相应的广义Green定理，首先研究了rpp半群H~(l-类、D~(l-类的若干基本性质，然后以左S-系、-双系和张量积作为工具，刻画了块Rees矩阵半群结构，最后从带零的本原rpp半群出发，构造出A型块Rees矩阵半群，并证明了一个半群S为本原rpp半群，当且仅当S同构于一个A型块Rees矩阵半群。

At the same time, they proved that a multipartite matroid is representable if and only if the corresponding discrete polymatroid is representable.

他们的工作具有令人振奋的结果：通过研究多部拟阵和离散多拟阵之间的关系，他们得到了多部存取结构为理想存取结构的一个必要条件和一个充分条件，并且证明了一个多部拟阵是可表示的当且仅当其对应的离散多拟阵是可表示的。

In this section, we also give a conjecture: A finite lattice is isomorphic to the lattice of flats of a finite poset matroid if and only if it is a semi-modular lattice.

本节的一个中心问题是提出了一个猜想：一个有限格L同构于一个有限偏序集拟阵的闭集所构成的格当且仅当L是一个半模格。

MoH for the test items if and only if there is no LOINC code to represent them.

检验项目，当且仅当LOINC 编码系统中没有相应的代码存在。

But at present only for some special cases of complete multipartite graphs, Ohba's conjecture have been verified.

容易发现Ohba猜想成立的条件是当且仅当它对完全多部图成立，但是目前只是就某些特殊的完全多部图的图类证明了Ohba猜想的正确性。

A topological spaces X is minimal CH if and only if for each x∈X and each open CH-filterbase μ,if {x}=∩U∈μU=∩U∈μclU, then μ is a neighborhood base of x.

4拓扑空间 X是极小 CH空间，当且仅当对任意的 x∈X和任意开 CH滤基μ，若{ x}=∩U∈μU=∩U∈μcl U，则μ是 x的一个邻域基。

In the present paper,we investigate solvable radicals and Hopkins nilpotent radicals for Lie triple systems and prove that both radicals are invariant under actions of deriva- tions.

本文讨论李三系的可解根基和Hopking幂零的某些性质及导子作用下的不变性，讨论了李三系次理想的某些性质，证明了李三系为幂零的当且仅当每个子系都是次理想。

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。