<P> The symbol is also used in differential geometry to denote a connection . </P> <P> A symbol of the same form, though presumably not genealogically related, appears in other areas, e.g.: </P> <Ul> <Li> As the all relation, particularly in lattice theory . </Li> <Li> As the backward difference operator, in the calculus of finite differences . </Li> <Li> As the widening operator, an operator that permits static analysis of programs to terminate in finite time, in the computer science field of abstract interpretation . </Li> <Li> As an indicator of indeterminacy in philosophical logic . </Li> <Li> In naval architecture (ship design), to designate the volume displacement of a ship or any other waterborne vessel; the graphically similar delta is used to designate weight displacement (the total weight of water displaced by the ship), thus ∇ = Δ / ρ (\ displaystyle \ nabla = \ Delta / \ rho) where ρ (\ displaystyle \ rho) is the density of seawater . </Li> </Ul> <Li> As the all relation, particularly in lattice theory . </Li>

What does an upside down triangle mean in mathematics