← First Pair Library

Glossary

Term Meaning in this companion
Adjoint Map transferring a linear operation across a dot product; the transpose for the real Euclidean coordinates here.
Anchor Reviewed pair representing the same entity in two maps for an alignment.
Article association Recorded candidate link between an article and a canonical person, with attribution evidence and review state.
Attention share Allocated scalar story attention divided by a stated source-period total.
Basis Independent directions used to express a space or subspace.
Calibration Agreement between modeled probabilities and observed label frequencies for a defined task.
Cell A specified source-and-decade grouping used for comparison and support.
Centering Subtracting the selected reference mean from observations.
Contrast A difference from a declared reference; a person contrast averages supported person-cell minus background rows.
Coordinate Amount along a named direction in a specified coordinate system.
Correlation Covariance divided by both coordinates’ positive standard deviations.
Covariance Average product of paired centered coordinates, with an explicit denominator convention.
Crosswalk Reviewed table connecting distinct vocabularies or representations while retaining their provenance.
Derivative Limiting rate of scalar output change per input change; a partial derivative varies one input while holding others fixed.
Discrimination Ability to distinguish positive and negative labeled cases, separate from calibration.
Eigenvalue and eigenvector A stretch factor and direction satisfying covariance times direction equals factor times direction.
Embedding Numerical representation of text produced by a specified model.
Frobenius norm Square root of the sum of squared matrix entries.
Gradient Collection of partial derivatives giving local changes of an objective with its parameters.
Held-out data Observations excluded from a stated fitting or tuning stage and reserved to evaluate it.
Incidence table Table marking which entities participate in which articles or events.
Intercept Baseline linear score when all input coordinates are zero.
Logistic function Map from a real score to a value between zero and one using the exponential function.
Mean Coordinate sum divided by its observation count, or a stated weighted counterpart.
Norm A length; the Euclidean norm here squares coordinates, adds them, and takes the square root.
Normalization Dividing a nonzero row by its own length to retain direction.
Ontology Reusable vocabulary of concepts and relationships among their meanings.
Orthogonal and orthonormal Perpendicular; perpendicular with unit length. An orthogonal square matrix changes orientation while preserving lengths.
PCA Principal component analysis: finding perpendicular directions of greatest variation in centered observations.
People pattern Learned direction of variation across person profiles.
Person profile A normalized, background-adjusted direction of one person’s associated news coverage.
Projection Measuring and retaining components along chosen directions.
Procrustes alignment Orthogonal fit aligning paired anchor rows by minimizing squared discrepancies.
Pseudoinverse Generalized inverse giving a least-squares solution, selecting the shortest when multiple solutions exist.
Rank Number of independent directions represented in a matrix.
Reconstruction Approximation rebuilt from retained coordinates.
Residual Original row minus reconstructed row, before any summary of its size.
Ridge penalty Added squared-slope cost that trades prediction fit against coefficient magnitude.
Singular value Nonnegative scale connecting left and right directions in an SVD.
Slope Coefficient multiplying one input coordinate in a linear prediction.
Standard deviation Nonnegative square root of variance.
Standardization Dividing coordinates by their reference standard deviations; mean subtraction must also be specified.
Subspace All weighted combinations of selected directions.
Support Eligible observed articles satisfying the stated profile gates; not a guarantee of statistical reliability.
SVD Singular value decomposition, factoring a table into left directions, nonnegative scales, and transposed right directions.
Trace Sum of a square matrix’s diagonal entries.
Variance Average squared centered coordinate value under a declared denominator convention.
Whitening Transformation giving unit variances and zero cross-coordinate covariance in the chosen retained space.