Simons and Sullivan constructed a model of differential K-theory, and showed that the differential K-theory functor fits into a hexagon diagram. They asked whether, like the case of differential characters, this hexagon diagram uniquely determines the differential K-theory functor. This article provides a partial affirmative answer to their question: For any fixed compact manifold, the differential K-theory groups are uniquely determined by the Simons–Sullivan diagram up to an isomorphism compatible with the diagonal arrows of the hexagon diagram. We state a necessary and sufficient condition for an affirmative answer to the full question. This approach further yields an alternative proof of a weaker version of Simons and Sullivan’s results concerning axiomatization of differential characters. We further obtain a uniqueness result for generalised differential cohomology groups. The proofs here are based on a recent work of Pawar.

西蒙斯（Simons）和沙利文（Sullivan）建立了微分K理论的模型，并证明了微分K理论函子适合六边形图。他们询问，是否像差分字符的情况一样，此六边形图是否唯一地确定了差分K理论函子。本文为他们的问题提供了部分肯定的答案：对于任何固定的紧凑型流形，微分K-理论组由西蒙斯-沙利文图唯一确定，直到与六边形图的对角线箭头兼容的同构。我们为整个问题的肯定答案规定了必要和充分的条件。这种方法进一步为西蒙斯（Simons）和沙利文（Sullivan）关于差分字符公理化的结果的较弱版本提供了另一种证明。我们进一步获得了广义微分同调群的唯一性结果。这里的证据是基于Pawar的最新著作。