Education that consists in learning things and not the meaning of them

is feeding upon the husks and not the corn. -- Mark Twain


... the learned have the right and the duty to use an obscure language that is comprehensible only to their fellows. -- Umberto Eco, The Name of the Rose


List of Symbols

a , b , v Attribute

v 0, v 1, ... Value for attribute

δ a , δ v 1, δ v 2 Change to an attribute

< a , δ a > Tuple of attribute a and change δ a to a

P, Q, T, E1, E2, T1, T2, S1, S2, ... Entity

P , Q , R Set of attributes

r Relationship

P Q Relationship between attribute sets P and Q

f , g Mapping function

I , J , I 1, I 2, ... Interaction

I.affects Effects determined by semantics of interaction I

I.affects + Effects of interaction I determined by dependencies

I.affects ∗ Effects of interaction I

E ( I ) Effects of interaction I

I J Concurrent occurrence of interactions I and J

E ( I ) ⋄ E ( J ) Applying E ( I ) and E ( J ) in some sequential order

E ( I ), E ( J ) Applying E ( I ) before E ( J )

t , t ´, ti , ti +1, tj , tj +1, t 0, t 1, ... Observation time, simulation time

[ ti , ti +1] Time-step

τ Duration of time-step

Δ P ( ti ) Changes to attribute set P during time-step [ti-1, t]

T , TA , TB , TM Sequence of observation times

Rep , RepA , RepB Set of all attributes in a model

Rel , RelA , RelB Set of all relationships in a model

Int , IntA , IntB Set of all interactions in a model

Model , ModelA , ModelB Model

LevelA , LevelB Representation level

Rep ( t ) State of a representation Rep at time t

Rel ( t ) Relationships in Rel that hold at time t

Int ( t ) Set of interactions in Int sent or received at time t

Int ( t ) k k th interaction in Int ( t )

Model ( t ) Model at time t

F ( Rep ( t ), E ( I )) Function that applies E ( I ) to state Rep ( t )

RepSeq Sequence of representation states

RelSeq Sequence of relationships that hold

IntSeq Sequence of set of interactions sent or received

RepM Set of all attributes in a multi-model

RelM Set of all relationships in a multi-model

Relcross-model Set of cross-model relationships in a multi-model

IntM Set of all interactions in a multi-model

ModelM Multi-model

⊕ Vector sum

➛ Transition in a state diagram

R( a ) Read operation on attribute/variable a

W( a ) Write operation on attribute/variable a

Z 1, Z 2, Z 3 Schedule of operations