invariants
Things that persist
Invariants are things that remain unchanged under specified conditions or transformations.
In mathematics and physics, an invariant is a property that holds constant even as other elements of a system change: The speed of light is an invariant in relativity theory.
In programming, invariants are conditions that must remain true throughout a process—a loop invariant holds at each iteration, a class invariant holds for every instance.
The concept extends to any domain where identifying what stays fixed helps understand what varies.
Preventing waste or loss
- symmetryInvariance under transformation
- constantFixed, unvarying quantity
- isomorphismStructure-preserving bijective map
- fixed pointValue unchanged by function
eigenvalue · characteristic · tensor · scalar · vector · covariant
Unchanging faithfulness over time
- permanenceQuality of lasting indefinitely
- immutabilityInability to change
- unchangeabilityInability to be modified
- stabilityResistance to displacement
persistence · regularity · uniformity · consistency · reliability · predictability · repeatability · determinism
Kept from deterioration
- unchangedNot modified at all
- fixed pointValue unchanged by function
- identityWho someone is
- equivalenceState of being equal
congruence · isometry · mapping · rotation · reflection · translation · scaling · affine
Confident statement of fact
- preconditionNecessary prior requirement
- contractEnforceable written agreement
- constraintLimiting condition or rule
- validationConfirming truth or accuracy
state · correctness · verification · data integrity · sanity check
Rule of unchanging totals
- energy conservationUnchanging total in closed systems
- angular momentumRotational motion quantity
- CPT symmetryCombined discrete transformation invariance
- parityState of being equal
conservation
Preventing waste or loss
- symmetryInvariance under transformation
- constantFixed, unvarying quantity
- isomorphismStructure-preserving bijective map
fixed point · eigenvalue · characteristic · tensor · scalar · vector · covariant
constancy
Unchanging faithfulness over time
- permanenceQuality of lasting indefinitely
- immutabilityInability to change
- unchangeabilityInability to be modified
stability · persistence · regularity · uniformity · consistency · reliability · predictability · repeatability · determinism · fixedness
preserved
Kept from deterioration
- unchangedNot modified at all
- fixed pointValue unchanged by function
- identityWho someone is
equivalence · congruence · isometry · mapping · rotation · reflection · translation · scaling · affine · projection
assertion
Confident statement of fact
- preconditionNecessary prior requirement
- contractEnforceable written agreement
- constraintLimiting condition or rule
validation · state · correctness · verification · data integrity · sanity check
conservation law
Rule of unchanging totals
- energy conservationUnchanging total in closed systems
- angular momentumRotational motion quantity
- CPT symmetryCombined discrete transformation invariance
invariantsvariables
Changeable elements in equations
variants · transients · volatiles · perturbations · flux
invariantsvariables
Changeable elements in equations
dependent variables · contingencies · degrees of freedom · unknowns