Graffiti scratch glass and other hard surfaces, such as permanent marking pens and markers or paint sticks; evidence of membership or affiliation with any gang or tagging crew, paraphernalia to include any reference to "(tagger's name)," and any drawings, writings, objects, or graffiti depicting taggers' names, initials, logos, monikers, slogans, or mention of tagging crew membership; any newspaper clippings relating details of or referring to any graffiti crime. Graffiti Graffiti (both singular and plural; the singular "graffito" is very rare in English except in archeology) is writing or drawings made on a wall or other surface, usually without permission and within
Singular homology on singular "n"-chains. The extension, called the boundary operator, written as is a homomorphism of groups. The boundary operator, together with the formula_25, form a chain complex of abelian groups, called the singular complex. It is often denoted as formula_26 or more simply formula_27. The kernel of the boundary operator is formula_28, and is called the group of singular "n"-cycles. The image of the boundary operator is formula_29, and is called the group of singular "n"-boundaries. It can also be shown that formula_30. The formula_31-th homology group of formula_32 is then defined as the factor group The elements of formula_34