While a generic smooth Ribaucour sphere congruence admits exactly two envelopes, a discrete R-congruence gives rise to a 2-parameter family of discrete enveloping surfaces. The main purpose of this paper is to gain geometric insights into this ambiguity. In particular, discrete R-congruences that are enveloped by discrete channel surfaces and discrete Legendre maps with one family of spherical curvature lines are discussed.

中文翻译：

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离散R-同余的Ribaucour族

普通的光滑Ribaucour球面全等值正好允许两个包络线，而离散的R等距则产生了一个包含离散包络面的2参数族。本文的主要目的是获得关于这种歧义的几何见解。特别地，讨论了由离散通道表面和具有一组球面曲率线的离散勒让德图包围的离散R同余。