Terminology
Page status: maintained glossary and translation aid.
This page records the preferred vocabulary used in definitions, claims, and certificates. Readers approaching from power engineering, software and data, mathematical modelling, graph theory, or graph machine learning should begin with One network, five languages.
The canonical editorial policy and its three usage statuses are defined in House policy: familiar words with explicit qualifiers. This page applies that policy as a lookup surface. Community terms are not declared synonyms merely because they occupy the same row: the vocabulary relation and the permitted editorial usage are separate classifications. For the exhaustive generated views, use the community-to-book and book-to-community indexes. Those indexes are generated from the controlled registry; this page remains the maintained definition surface.
Cross-community collision index
| Familiar term or cluster | Required question in this book | Common unsafe inference |
|---|---|---|
| bus, node, vertex, junction, terminal, port | What object type and representation? | every node is one physical bus |
| line, branch, edge, arc, relation, nonzero | What owns identity and what records attachment or coupling? | every graph edge is one physical branch |
| factor | Behavioural relation, factor-graph node, power factor, or matrix factor? | these uses are interchangeable |
| graph, topology, adjacency | Asset, active-connectivity, factor-incidence, equation, support, or message graph? | one topology answers every query |
| directed, oriented, upstream, downstream | Stored order, operating sign, rooted-tree relation, causality, or admissibility? | an arrow predicts physical transfer |
| flow, current, power, message | Which terminal or internal quantity and which conservation law? | one antisymmetric scalar lives on every edge |
| parallel | Same endpoints, same terminals, shared physical route, homogeneous equipment, or parallel computation? | members can be merged without a contract |
| cycle, loop, mesh, radial | In which graph and active state? | a graph cycle is a circulating physical flow |
| state | Electrical variables, equipment status, scenario, estimator state, or ML hidden state? | one state object contains all of them |
| rating, limit, constraint | Source datum, operational policy, or mathematical encoding? | one scalar constraint reproduces the equipment limit |
| equivalent, exact, preserving | Which interface and preservation object? | equal terminal equations imply equal decisions |
| projection, compilation, elimination, aggregation, reduction, pooling | Which objects are changed, forgotten, solved, or recoverable? | every operation merely makes a graph smaller |
| normalization | Per-unit, coordinate, schema, physical-model, or feature normalization? | all normalizations preserve the same semantics |
| loss | Electrical dissipation, information loss, or training objective? | a shared word implies a shared quantity |
| ground, neutral, reference | Physical earth, conductor, impedance, or gauge choice? | all are one zero-voltage node |
| phase, conductor, sequence, coordinate | Asset label, physical path, terminal slot, phase-domain quantity, or transformed coordinate? | one label fixes every coordinate and transformation |
| label, index, coordinate, array position | Semantic object identity or storage location? | an integer row/column is the physical bus, line, or cycle identity |
The sections below give the compact house definitions. Detailed counterexamples belong to Translation traps; rigorous graph objects belong to Representation frameworks.
| Term | Meaning in this book | Definition or route |
|---|---|---|
| Asset | A physical or organizational entity with stable identity and lifecycle facts | Frameworks |
| Port | A typed interface at which variables interact with a component or subsystem | Frameworks |
| Junction | An interconnection object imposing equality/conservation structure | Frameworks |
| Factor | A constitutive, control, limit, measurement, or decision relation over ports | Frameworks |
| Hierarchy | Explicit containment with declared subsystem boundary ports | Frameworks |
| Projection | A map that forgets distinctions without solving governing equations | Transformation register |
| Compilation | Replacement of a high-level component by a realization in a target vocabulary | Transformation register |
| Normalization | A semantics-preserving rewrite into a selected canonical physical/model form | Transformation register |
| Behavioral reduction | Elimination of hidden variables preserving a declared external relation | Projection, compilation, and reduction |
| Approximate reduction | Reduction with a stated observation domain, metric and error | Projection, compilation, and reduction |
| Preservation contract | Precise statement of retained observations, constraints, assumptions and recovery | Contracts |
| Limit disposition | Six-way classification of a source limit as retained, mapped, conservative, relaxed, scenario/uncertain, or forgotten | Rating semantics |
| Observed-set class | Feasible-set relation classified as exact, inner/conservative, outer/relaxed, or scenario-approximate | Preservation contracts |
| Recovery map | Map from retained/reduced variables to eliminated source quantities | Contracts |
| Provenance | Traceable correspondence among source, generated and reduced objects | Source architecture |
| Morphism | A map preserving the declared structure within one representation framework | Representation maps |
| Isomorphism | A reversible morphism; a change of names or coordinates rather than a quotient or compilation | Representation maps |
| Query factorization | Evidence that a source query can be answered from a target because it factors through the declared transformation | Contracts |
| Computational dependency graph | A graph whose vertices and edges encode declared variables, equations, operations, or dependencies rather than physical equipment | Frameworks |
| Message graph | The compiled graph on which a graph-learning architecture exchanges messages; its nodes and edges need not be physical buses and branches | Vocabulary bridge |
| Feature | An attribute supplied to a statistical or learned model; physical meaning exists only through its source map, units, coordinate convention, and state association | Vocabulary bridge |
| Pooling | A many-to-one learned or algorithmic aggregation whose sufficiency is relative to a downstream query and retained side information | Transformation register |
| Electrical state | The declared continuous electrical variables at an operating point, distinct from equipment status, scenario labels, estimator metadata, and learned hidden state | Load models |
| Equipment state | A discrete or continuous device condition such as switch status or tap position, with source identity and admissible transitions retained | Topology processing |
| Neutral conductor | An explicit conductor with voltage, current, connectivity, ratings, and provenance rather than a synonym for earth or reference | Earth and neutral |
| Voltage reference | A gauge choice used to select a voltage representative; not automatically physical earth or a neutral conductor | Earth and neutral |
| Terminal coordinate | One ordered component of a declared terminal interface vector | Notation and modelling conventions |
| Label-indexed relation | A family of quantities indexed by semantic sets such as buses, lines, terminals, or cycles | Notation and modelling conventions |
| Enumeration | An explicit bijection from a semantic finite set to integer storage positions | Notation and modelling conventions |
| Array position | An implementation row, column, or tensor slot after enumeration; not an asset identity | Notation and modelling conventions |
| Sequence coordinate | A transformed combination of phase-domain coordinates under a declared basis | General-model collapse |
| Asset/terminal topology | Identified high-level equipment and its port or bus attachments; a multigraph only for the genuinely two-terminal subset | Frameworks |
| Conductor/port–factor topology | Electrical conductor junctions, typed ports, and constitutive factors, with terminal maps and coupling retained | Frameworks |
| Block-support graph | Simple graph with one vertex per retained nodal block and an edge for each nonzero off-diagonal block of an assembled operator | Two-level topology |
| Scalar-support graph | Simple graph on retained scalar coordinates, with edges determined by nonzero matrix entries rather than asset identity | Two-level topology |
| Stamp multigraph | Derived decomposition that retains one identified member for each separate factor stamp contributing to an assembled matrix | Two-level topology |
| Simple cycle | A closed cycle of at least three distinct vertices in a loopless simple graph | Cycles and radiality |
| Line-identity cycle | A minimal-support nonzero vector in the incidence nullspace of an identified multigraph | Cycles and radiality |
| Physically parallel sections | Line sections that overlap spatially on common towers, poles, trench, or right of way for a declared interval; not necessarily graph-parallel, electrically interchangeable, or part of one transfer corridor | Coupled corridor |
| Parallel fibre | The set of identified elements mapped to one unordered endpoint pair by the simple quotient | Cycles and radiality |
| Mutual-coupling record | An oriented relation between two identified line sections carrying cross blocks, coordinate maps, overlap, and provenance | Coupled corridor |
| Coupling group | A connected component of the section-level mutual-coupling relation | Coupled corridor |
| Joint primitive | The impedance, admittance, or terminal relation assembled for a complete coupling group before any optional nodal or ordinary-edge lowering | Coupled corridor |
| Bridge | An identified edge whose deletion increases the number of connected components in the declared graph | Cycles and radiality |
| Radial tail | A maximal bridge path ending at a leaf in a specified graph and active state | Cycles and radiality |
| Adjacency-radial | Forest property of the simple topology projection | Cycles and radiality |
| Member-radial | Forest property of the identified line multigraph | Cycles and radiality |
| Terminal power | Complex-power injection at one declared device terminal; generally one member of a two-end or multiport observation tuple | Orientation and power |
| Energized | Connected through the declared active device states to an admissible source under the study's electrical semantics | Earth and neutral |
| Complex symmetric | Matrix satisfying $\mathbf A^{\mathsf T}=\mathbf A$; not synonymous with Hermitian | Translation traps |
| Physical merge | Rewrite asserting that source assets are subdivisions or representations of one target asset | Transformation register |
| Composite equivalent | Behavioral object representing several source components without claiming homogeneous physical identity | Transformation register |
| Closure | Property that a model class remains in the same class under a transformation | Transformation register |
| Confluence | Property that different valid rewrite orders reach equivalent normal forms | Transformation register |
| Structure-preserving transformation | A typed bijective map or coordinate action that commutes with the declared incidence and relation structure | Transformation register |
| Decision-preserving transformation | A transformation whose mapped feasible decisions, objective and declared source constraints agree under the stated contract | Contracts |
| Composite factor | A target factor that preserves a declared relation for several source assets without claiming they are one homogeneous physical asset | Transformation register |
| Type-safe composition | Composition accepted only when ports, factor classes, units, states and constraint ownership satisfy a declared rule | Transformation register |
| Anti-pattern | A tempting rewrite that is algebraically suggestive but violates a type, preservation or observation precondition | Translation traps |
| Rooted active-tree view | A state- and root-dependent parent/child orientation of a radial active graph used by an algorithm or feeder recursion | Cycles and radiality |
| Parent edge | The unique active-tree edge connecting a non-root node to its predecessor on the selected root path | Cycles and radiality |
| Chord | An active member omitted from a selected spanning forest; it closes a cycle and is not intrinsically upstream or downstream | Cycles and radiality |
| Upstream/downstream | A qualified hierarchy label relative to a declared root, active state and tree; never an unqualified property of a passive asset | Cycles and radiality |
| Source-distance | A graph metric or path relation from a designated source, which may remain meaningful in a mesh even when parenthood is not unique | Cycles and radiality |
Terms to use carefully
Structure preserving
Always qualify the structure: Laplacian, sparsity, radiality, phase connectivity, port-Hamiltonian form, equipment class, asset correspondence, limits, or dynamic equations. The unqualified phrase is too ambiguous.
Equivalent
State the interface, operating/model domain, joint observations, constraints, objective correspondence, and recovery obligations. Matching separate ranges does not establish their joint feasible image. State whether the claim is exact, conservative, relaxed, or approximate.
Bus
Distinguish at least:
- physical busbar or busbar section;
- connectivity node;
- state-dependent topological node;
- mathematical nodal variable group;
- reporting or planning bus.
Nodal-admittance graph
State whether this means block support, scalar conductor-coordinate support, or a retained stamp decomposition. The first two are simple support graphs of an operator. They do not recover the identified asset multigraph that was assembled into that operator.
Line
Distinguish:
- physical circuit or cable system;
- homogeneous construction segment;
- model section introduced by discretization;
- mathematical two-port branch;
- behavioral equivalent with no single physical counterpart.
Parallel
Distinguish physically parallel line sections, topological parallel edges, terminal or electrical parallelism, and operational interchangeability. Physically parallel follows line-modeling usage for spatially co-located sections; it is not the transfer meaning of corridor. Electromagnetic mutual coupling is a separate relation and can exist between sections at different voltage levels and with different endpoint pairs.
Mutual coupling
A mutual-coupling record is a relation over two oriented line sections. Its connected components are coupling groups, and each group is assembled into one joint primitive. These source objects remain distinct from any generated weighted-lattice realization of the primitive.
Flow
Distinguish a commodity-flow variable, an internal series current, a terminal current, a terminal complex power, and an observed operating-point transfer. A lossy AC branch generally has a pair of terminal powers rather than one conserved edge-flow scalar.
Directed
State whether direction means stored orientation, terminal-current sign, positive power reference, observed operating transfer, causal dependency, or one-way admissibility. These meanings do not imply one another.
Connected and energized
Graph connectivity is a structural predicate. Energization additionally depends on active state, admissible sources, terminal connectivity, and the electrical semantics of the study.
Ground, neutral, and reference
Distinguish physical earth or an earth-return model, a neutral conductor, a grounding impedance or connection, and a voltage reference used to remove gauge freedom. A neutral voltage may be eliminated from a reduced coordinate system while its recovered current, rating, grounding path, and protection meaning remain part of the source feasible set.
Phase, conductor, sequence, and coordinate
State whether phase names an asset label, a physical conductor, a bus terminal, a phase-domain component, or a reporting aggregate. A terminal coordinate is an ordered interface slot; a sequence component is a transformed coordinate. Conductor permutations, phase discontinuities, and sequence transforms therefore require declared maps rather than matching labels alone.