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Notation and shapes

All observation vectors in this companion are rows. A matrix direction, such as a column of WW, is a column. The shapes below summarize the definitions introduced in the chapters. The letter nn counts fitted people; NN counts reviewed training articles for the proposed calibration fit.

Symbol Shape Meaning
xa,μx_a,\mu 1×d1\times d Article embedding and its fitted reference mean
VV d×Kd\times K Retained raw news directions
R,DR,D K×KK\times K Naming rotation and named-axis scale matrix
ca,ya,zac_a,y_a,z_a 1×K1\times K Raw, named, and standardized article coordinates
qg,mpgq_g,m_{pg} 1×K1\times K Cell background and person-cell mean
rp,bpr_p,b_p 1×K1\times K Balanced contrast and its unit direction
B,HB,H n×Kn\times K Unit person rows and their centered rows
b‾\bar b 1×K1\times K Mean unit person profile in the fitted population
CPC_P K×KK\times K Equal-person covariance
WW K×rK\times r Retained people-pattern loadings
upu_p 1×r1\times r A person’s retained people coordinates
WW𝖳WW^{\mathsf T} K×KK\times K Rank-rr projector in news-coordinate geometry
Z,YZ,Y N×KN\times K, N×mN\times m Article inputs and reviewed concept targets
A,βA,\beta K×mK\times m, m×1m\times1 Proposed concept slopes and intercepts
W𝖳AW^{\mathsf T}A r×mr\times m Algebraic slopes from people directions to concept scores

Here d=384d=384, K=60K=60, and r=24r=24 in the published models described by the paper; the main fictional example uses K=3K=3 and r=2r=2. The bare rr is a retained dimension count; the indexed rpr_p is a person’s contrast row. The hypothetical number of ontology targets, mm, is a modeling choice rather than a statement that every ontology concept has a trained classifier.

In the thin SVD H=UΣQ𝖳H=U\Sigma Q^{\mathsf T}, k*=min⁡(n,K)k_*=\min(n,K). The matrix UU is n×k*n\times k_*, Σ\Sigma is k*×k*k_*\times k_*, and QQ is K×k*K\times k_*. Selecting the first rr columns of QQ with the fitted orientation produces WW; the corresponding columns of UU and diagonal block of Σ\Sigma produce the score matrix UrΣrU_r\Sigma_r. Coordinate sums SpgwS_{pgw} and concept-score rows ss are different objects.

Time-window subscripts extend the same shapes: bpw,qgw,mpgwb_{pw},q_{gw},m_{pgw} have KK coordinates, while upwu_{pw} has rr. The displacement Δp\Delta_p, discarded squared length QpQ_p, attention share αa\alpha_a, and ranking score are scalars. In the alignment example, X,YX,Y are M×kM\times k anchor tables and QalignQ_{\mathrm{align}} is the k×kk\times k orthogonal map; that use of YY is local to alignment.