In this paper, a new system for classification of online isolated handwritten Arabic characters on a handheld device (Palm Pilot) is introduced. Unlike other languages, Arabic has many characters that cannot be written in one stroke. The first stroke of most of these characters is identical. That led us to design a new Arabic graffiti. A neural network was used for classification. It achieved a...

Let R(T ), D(T ) be respectively the radius and diameter of a nontrivial tree T and I(T ) = ∑ u∈V (T ) 1/d(u) be the inverse dual degree, where d(u) = ( ∑ v∈N(u) d(v))/d(u) for each u ∈ V (T ). In this note we prove that I(T ) ≥ { R(T ) + 1/3, if D(T ) is odd R(T ) + 5/6, if D(T ) is even, with equality if and only if T is a path of at least 4 vertices. This inequality strengthens a conjecture ...

The paper ‘‘Mean Distance and Minimum Degree,’’ by Mekkia Kouider and Peter Winkler, JGT 25#1 (1997), 95–99 mistakenly attributes the computer program GRAFFITI to Fajtlowitz and Waller, instead of just Fajtlowitz. (Our apologies to Siemion Fajtlowitz.) Note also that one of the ‘‘flaws’’ we note for Conjecture 62 (that it was made for graphs regular of degree d, vice graphs of minimum degree d)...

This study examines how social cohesion is built through exchange of urban art. Graffiti and street art are treated like dirt and washed away. Unsanctioned art is often perceived as alien to museums and private homes. Despite this, many graffiti and street artists produce art in studios that are sold in galleries as urban art. Through ethnographic tools and site visits to homes of collectors in...