论文标题
(积极)完全有序的非交通性单型 - 它们的非交换性如何?
(Positive) Totally Ordered Noncommutative Monoids -- How Noncommutative Can They Be?
论文作者
论文摘要
换向的完全有序的单体有比比皆是,例如数字系统。如果不假定单型可交换性,则可能很难按下一个示例。 Orr Shalit教授的建议是增加的序列。 在本说明中,我们尝试对完全(部分)订购的单体序列(也没有假定为可交换)进行介绍性调查,并将它们视为正面,即每个元素都大于单位元素。在通常的交换案例中,可以通过代数结构定义订单,即分裂性(从我们的添加意义上):$ a \ le b $定义为$ \ cancesists \ c \,c \,\,(b = a+c)$。非公共案例提供了几种概括的方法。 首先,我们尝试遵循分裂性定义(右侧或左侧)。然后,我们坚持要订购与左侧和右侧的操作兼容的订单,但严格的不平等可能不会延续 - 再次参考序言示例。我们试图查看这种要求对单体结构施加的公理,并建立了一些事实。 特别关注完全有序的案例,人们发现一定有限的不合作力是有限的。一个人可能在这里部分模仿了交换性案例,谈到无限的刨丝机与\ aChimedean彼此相互元素,在阿基米德案中,甚至模仿了欧几里得的元素的“比率”理论 - 所有这些都施加了某种局部交换性。
Commutative totally ordered monoids abound, number systems for example. When the monoid is not assumed commutative, one may be hard pressed to find an example. One suggested by Professor Orr Shalit are the countable ordinals with addition. In this note we attempt an introductory investigation of totally (also partially) ordered monoids, not assumed commutative (still writing them additively), and taking them as positive, i.e.\ every element is greater than the unit element. That, in the usual commutative cases, allows the ordering to be defined via the algebraic structure, namely, as divisibility (in our additive sense): $a\le b$ defined as $\exists\,c\,\,(b=a+c)$. The noncommutative case offers several ways to generalize that. First we try to follow the divisibility definition (on the right or on the left). Then, alternatively, we insist on the ordering being compatible with the operation both on the left and on the right, but strict inequality may not carry over -- again refer to the ordinals example. We try to see what axiom(s) such requirements impose on the monoid structure, and some facts are established. Focusing especially on the totally ordered case, one finds that necessarily the noncommutativity is somewhat limited. One may partly emulate here the commutative case, speaking about infinitely grater vs.\ Archimedean to each other elements, and in the Archimedean case even emulate Euclid's Elements' theory of `ratios' -- all that imposing some partial commutativity.