invariant

adj

1. Not varying; constant.
2. Unaffected by a specified operation, especially by a transformation.

   “The fundamental 2-tensor also leads to a new class of invariant linear differential operators that are canonically associated to these geometries; included is a third equation studied by Gallot et al. We apply the results to study the metrisability equation, in the nullity setting described.”

3. Neither covariant nor contravariant.

noun

1. An invariant quantity, function etc.

   “In the present paper this criterion is reformulated in terms of pseudotensorial invariants of the form..”

2. (abbreviation, alt-of, ellipsis)Ellipsis of class invariant.