The Matrix is the latest generation Frequency-Doubling Technology (FDT) perimeter, introduced to the eye care professions in 2003. With seven tests available, visual field testing can proceed from the macula to an eccentricity of thirty degrees. Its ability to detect magnocellular pathway deficiencies has made FDT an excellent tool in the management of glaucoma. The purpose of this article is t...

A rainbow matching in an edge-colored graph is a which no two edges have the same color. The color degree of vertex v number distinct colors on incident to v. Kritschgau [Electron. J. Combin. 27(3), 2020] studied existence matchings G with average at least 2k, and proved some sufficient conditions for marching size k G. include that $$|V(G)|\ge 12k^2+4k$$ , or properly 8k$$ . In this paper, we ...

We prove that if the average of the degrees of the irreducible characters of a finite group G is less than 16/5, then G is solvable. This solves a conjecture of I. M. Isaacs, M. Loukaki and the first author. We discuss related questions.