7.20.1 Tensor Redundant Component Equality Relation
Tensor Redundant Component Equality Relation identifies when tensor components are equal through algebraic simplification.
Tensor Redundant Component Equality Relation is the formal mathematical relation linking each redundant position in a tensor's component table to the specific independent position from which its value is derived, together with the exact rule, whether direct equality or sign reversal, that governs the correspondence between the two.
Structure of the Relation
A Relation Between Positions, Not Merely Values
The Tensor Redundant Component Equality Relation is defined not simply as a statement that two numbers are equal, but as a pairing between two specific positions in a tensor's index space, together with the transformation connecting the value at one position to the value at the other. For a redundant position obtained by exchanging a Tensor Component Symmetric Index Pair, the relation is:
while for a redundant position obtained by exchanging a Tensor Component Antisymmetric Index Pair, the relation instead reads:
Uniqueness of the Corresponding Independent Position
For a given Tensor Independent Component Selection, every redundant position is linked by this relation to exactly one independent position, ensuring that the relation defines a well-defined pairing rather than an ambiguous association with several possible sources.
Illustration
The arrow represents the Tensor Redundant Component Equality Relation, pointing from the independent position to the redundant one and carrying the specific rule that fixes the redundant value.
Properties of the Relation
Consistency With Repeated Application
If the Tensor Redundant Component Equality Relation is applied twice, by treating the redundant position as though it were itself being related back to the original position through the same exchange, the result is consistent with the starting value. For a symmetric relation, applying the rule twice returns the original value unchanged, while for an antisymmetric relation, applying the rule twice multiplies the value by negative one twice, likewise returning the original value.
Compatibility With the Reconstruction Role
The Tensor Redundant Component Equality Relation is precisely the mechanism exercised by the Tensor Independent Component Reconstruction Role when recovering the full component table from the independent values, since reconstructing a redundant position amounts to nothing more than evaluating the relation for that position using the corresponding independent value.
Scope of the Relation
Applies Position by Position
The Tensor Redundant Component Equality Relation is defined separately for each redundant position, rather than as a single global statement about the tensor. In a tensor with multiple redundant positions arising from different index pairs, each redundant position has its own instance of the relation, linking it to its own corresponding independent position through whichever rule is appropriate to the pair responsible for that redundancy.
Basis Independence of the Relation
Because the underlying equality and sign-change rules are preserved under any admissible coordinate transformation, by virtue of Tensor Component Object Preservation, the pairing between a redundant position and its corresponding independent position, together with the rule connecting them, remains the same in every coordinate system, even as the specific numerical values at both positions generally change.
Relationship to Other Tensor Concepts
Tensor Redundant Component Equality Relation supplies the precise formal statement underlying the broader notion of a Tensor Redundant Component Symmetry Source, specifying not merely that redundancy exists but exactly how each redundant position is derived from its corresponding independent position. It is the operational counterpart, within the Tensor Redundant Component Structure, to the reconstruction process described by the Tensor Independent Component Reconstruction Role.