13.3 Atoms: Their Types and Weights 253 of pure functional programming formalisms like combinatory logic. However, this purely func- tional style has not proved convenient, so the Atomspace in practice combines functional-style representation with variable-based representation. Temporal links often come with specific temporal quantification, e.g. PredictivelImplicationLink <5 seconds> EvaluationLink JumpOffCliff $x EvaluationLink Dead $X indicating that the conclusion will generally follow the premise within 5 seconds. There is a system for managing fuzzy time intervals and their interrelationships, based on a fuzzy version of Allen Interval Algebra. SequentialANDLink is similar to PredictivelmplicationLink but its truth value is calculated differently. The truth value of SequentialANDLink <5 seconds> EvaluationLink JumpOffCliff $x EvaluationLink Dead $X indicates the likelihood of the sequence of events occurring in that order, with gap lying within the specified time interval. The truth value of the PredictivelmplicationLink version indicates the likelihood of the second event, conditional on the occurrence of the first event (within the given time interval restriction). There are also links representing basic temporal relationships, such as BeforeLink and Af terLink. These are used to refer to specific events, e.g. if X refers to the event of Ben waking up on July 15 2012, and Y refers to the event of Ben getting out of bed on July 15 2012, then one might have AfterLink X ¥ And there are TimeNodes (representing time-stamps such as temporal moments or intervals) and AtTimeLinks, so we may e.g. say AtTimeLink Xx TimeNode: 8:24AM Eastern Standard Time, July 15 2012 AD 13.3.5 Associative Links There are links representing associative, attentional relationships, e HebbianLink e AsymmetricHebbianLink e InverseHebbianLink e SymmetricInverseHebbianLink These connote associations between their arguments, i.e. they connote that the entities repre- sented by