The paper aims at developing the idea that the standard operator of noncontingency, usually symbolized by Δ, is a special case of a more general operator of dyadic noncontingency Δ(−, −). Such a notion may be modally defined in different ways. The one examined in the paper is Δ(B, A) = _df ◊B ∧ (A ⥽ B ∨ A ⥽ ¬B), where ⥽ stands for strict implication. The operator of dyadic contingency ∇(B, A) is defined as the negation of Δ(B, A). Possibility (◊A) may be then defined as Δ(A, A), necessity (□A) as ∇(¬A, ¬A) and standard monadic noncontingency (ΔA) as Δ(\({\textsf{T}}\), A). In the second section it is proved that the deontic system KD is translationally equivalent to an axiomatic system of dyadic noncontingency named KDΔ², and that the minimal system KΔ of monadic contingency is a fragment of KDΔ². The last section suggests lines for further inquiries.

本文旨在发展这样一种观点，即通常用 Δ 表示的非偶然性标准算子是二元非偶然性 Δ(-, -) 的更一般算子的一个特例。这样的概念可以以不同的方式模态定义。论文中考察的是Δ (B, A) =  _df ◊B ∧ (A ⥽ B ∨ A ⥽ ¬B)，其中⥽代表严格蕴涵。二元偶然性∇ (B, A) 的算子被定义为Δ (B, A) 的否定。可能性 (◊A) 可以定义为Δ (A, A)，必要性 (□A) 可以定义为∇ ( ¬A , ¬A)，标准一元非偶然性 (ΔA) 可以定义为Δ ( \({\textsf{T} }\)， 一种）。第二部分证明了道义系统KD平移等价于一个名为KDΔ2的二元非偶然性公理系统^{，并且一元偶然性的最小系统KΔ}是KDΔ2的一个片段。最后一节建议进一步查询的线路。