Abstract:
The notion of digital straightness has been studied since Azriel Rosenfeld's seminal paper of 1974. In particular, characterizations using the chord property, word combinatorics, and double Diophantine inequalities have been investigated. To these I will add characterizations using difference operators and show how these four aspects relate to each other. If time permits, I will also discuss the related, more general notion of digital convexity—as is to be expected, convexity and concavity jointly is equivalent to straightness.