Go-go dancing 1960s-era clubgoers wore miniskirts and knee-high, high-heeled boots, which eventually came to be called go-go boots. Night club promoters in the mid‑1960s then conceived the idea of hiring women dressed in these outfits to entertain patrons. The term "go-go" derives from the phrase "go-go-go" for a high-energy person, and was influenced by the French expression "à gogo", meaning "in abundance, galore", which is in turn derived from the ancient French word "la gogue" for "joy, happiness". On 19 June 1964, Carol Doda began go-go dancing topless at the Condor Club on Broadway and Columbus in the North Beach neighborhood of
Nested word context-free grammars. A visibly pushdown grammar "G" is defined by the 4-tuple: formula_105 where Here, the asterisk represents the Kleene star operation and formula_131 is the empty word. The problem whether a word of length formula_1 is accepted by a given nested word automaton can be solved by uniform boolean circuits of depth formula_133. Regular languages over nested words are exactly the set of languages described by Monadic second-order logic with two unary predicates "call" and "return", linear successor and the matching relation ↝. Nested word In computer science, more specifically in automata and formal language theory, nested words are