ML: Kv cache

Machine-learning ideas tagged Kv cache in the ML taxonomy of the Math2NN corpus.

35 ideas found

△ Mechanism confirmed, baseline not beaten 2026

Rate-adaptive KV-cache quantizer

Allocate different entropy budgets to different KV-cache blocks instead of assigning every token and head the same nominal bitwidth. Use the ECASQ Lagrangian so high-variance or attention-sensitive blocks receive more codepoints, while predictable blocks collapse to fewer symbols and become highly compressible. Preserve unbiasedness per scalar or block so reconstructed keys and values have zero mean quantization error conditional on the original tensor.

Useful8/10
Difficulty6/10
Novelty7/10
Paper: Entropy-Constrained Adaptive Stochastic Quantization arXiv:2608.18147
△ Mechanism confirmed, baseline not beaten 2026

Entropy-constrained unbiased block quantization

Replace fixed-grid stochastic quantization of each tensor block with an adaptive ordered codebook selected under both an entropy budget and a maximum number of codepoints. Within every interval between adjacent codepoints, use unbiased stochastic interpolation, so the quantized block remains unbiased while the emitted symbol distribution becomes easier for arithmetic or Huffman coding to compress. The representation should reduce actual compressed bytes at fixed MSE, or reduce MSE at fixed…

Useful8/10
Difficulty6/10
Novelty6/10
Paper: Entropy-Constrained Adaptive Stochastic Quantization arXiv:2608.18147
✗ Failed on benchmark 2026

Equal-Volume KV Vector Quantization

Replace consecutive or randomly assigned transformed KV coefficients with groups whose variance-volume is approximately equal. Train one equal-size vector-quantizer codebook per group, so a fixed-width cache does not waste its low-rate budget by forcing high-variance and low-variance coordinates into badly mismatched groups. This is a drop-in quantization-layout change that can be applied to keys, values, or both.

Useful8/10
Difficulty5/10
Novelty7/10
Paper: Spend Bits Where Queries Look: KV Cache Vector Quantization with Attention-Preserving Transforms arXiv:2608.04074
✗ Failed on benchmark 2026

Rank-One PSD KATA Attention

Replace the usual random or elementwise-positive linear-attention feature map with a rank-one positive-semidefinite feature map derived from query and key vectors. For normalized inputs, the resulting kernel is the squared inner product, which is nonnegative and gives a geometrically structured interference pattern that is better suited to associative recall than an arbitrary low-rank feature map.

Useful8/10
Difficulty6/10
Novelty7/10
Paper: Kernelized Linear Attention: Breaking the Capacity Wall with Symmetric Cones arXiv:2607.17419
△ Mechanism confirmed, baseline not beaten 2026

Joint Tucker-rank and residual-bit KV allocator

Compress each layer's KV tensor with a partial Tucker approximation over token and feature axes, then encode the truncation residual with a rotated uniform quantizer. Select token rank, feature rank, and residual bit-width jointly under a global byte budget, allowing values with flat spectra to receive residual bits while keys may receive more low-rank capacity.

Useful8/10
Difficulty6/10
Novelty6/10
Paper: A JoLT for the KV cache: Near-lossless KV cache compression via joint Lagrangian allocation of Tucker ranks and a rotated residual for llms arXiv:2607.12550
△ Mechanism confirmed, baseline not beaten 2026

Equal-Variation KV Cache

Compress a causal sequence by retaining history positions at equal increments of cumulative representation variation instead of at uniform time intervals. Use the resulting N representatives in a decoder that reconstructs piecewise-constant keys and values; the paper's minimax result predicts a worst-case reconstruction error of total variation divided by 2N, independent of where rapid changes occur.

Useful8/10
Difficulty5/10
Novelty6/10
Paper: Optimal history encoding for elastic-plastic hereditary laws: Sharp input and constitutive approximation arXiv:2607.09974
△ Mechanism confirmed, baseline not beaten 2026

DP-Means Distinct-Item Memory

Replace token-by-token KV storage after an SSM or recurrent encoder with an online allocate-on-novelty cache. A new slot is created only when the incoming key is sufficiently dissimilar from every stored key; otherwise the incoming value is merged into its nearest slot, so repeated or redundant content does not grow the cache.

Useful8/10
Difficulty4/10
Novelty6/10
Paper: Remembering Distinct Items, Not Tokens: A Learnable Dirichlet-Process Cache Between State-Space Models and Attention arXiv:2607.09889
✗ Mechanism failed 2026

Ranking-Aware Projection Dimension Rule

Replace the usual JL dimension choice with a task-specific dimension budget based on the paper's asymptotic ranking law. For retrieval, nearest-neighbor search, or compressed attention keys, choose m from a target Kendall correlation and automatically expand the projection when measured ranking quality falls below the target.

Useful7/10
Difficulty3/10
Novelty7/10
Paper: Exact Limits of Random Projections for Preserving Geometry: Distance Recovery, Nearest-Neighbor Rankings, and Covariance Shape in Gaussian Models arXiv:2609.02155
△ Mechanism confirmed, baseline not beaten 2026

Residual-Pivoted Kernel Attention

Replace full PSD self-attention with a pivoted Cholesky/Nyström approximation whose landmarks are sampled from the unexplained diagonal mass. Tokens with large residual self-similarity are more likely to become landmarks, so the rank budget is spent on difficult regions rather than uniformly selected tokens.

Useful7/10
Difficulty5/10
Novelty5/10
Paper: A new analysis of the randomly pivoted Cholesky algorithm arXiv:2608.20633
✗ Mechanism failed 2026

Permutation-Mixed Orthogonal Quantization

Precondition activation or cache blocks with a fixed product U = A Sigma B of orthogonal transforms and a random signed permutation before quantization or coordinate sampling. The random permutation makes the product incoherent, so energy is less concentrated in a few coordinates and lossy compression should introduce less worst-case distortion.

Useful7/10
Difficulty5/10
Novelty5/10
Paper: Randomly Permuted Orthogonal Products and Fast Dimension Reduction arXiv:2608.18557
△ Mechanism confirmed, baseline not beaten 2026

Orthogonally mixed 3-bit KV cache

Replace ordinary per-channel or per-token KV quantization with a structured orthogonal transform followed by blockwise 3-bit quantization. Use a normalized Walsh-Hadamard transform and small SO(4) rotations to spread outliers across coordinates, quantize the transformed vectors, and exploit orthogonality to rotate queries and attention outputs so unquantized attention remains mathematically equivalent.

Useful7/10
Difficulty6/10
Novelty6/10
Paper: RotaryQuant: Fitting 120B MoE Models on Consumer Hardware via Fused Compressed-Space Attention arXiv:2608.08081
△ Mechanism confirmed, baseline not beaten 2026

Lipschitz-Certified Cache Refresh

Attach a certificate to a cached transformer KV state or recurrent latent state and refresh it only while its predicted certificate remains inside a latency-contracted admissible region. The controller uses a bound on certificate drift to guarantee that the state will remain admissible throughout the next sampling, communication, and execution delay, reducing unnecessary recomputation while exposing a measurable refresh boundary.

Useful7/10
Difficulty5/10
Novelty8/10
Paper: CIPS: Maximal Certified Persistence in Cyber-Physical Systems arXiv:2608.06626
△ Mechanism confirmed, baseline not beaten 2026

Spectral Message Basis

Replace full agent-to-agent state transmission with coefficients in a learned dominant Koopman mode basis. Agents communicate only the leading spectral coordinates that explain slowly decaying collective behavior, while retaining a certificate based on the spectral gap and subdominant eigenvalue to decide whether the compressed representation is safe.

Useful7/10
Difficulty6/10
Novelty6/10
Paper: Certifying Collective Reasoning in Multi-Agent Systems via Koopman Spectral Analysis arXiv:2608.05956
✗ Failed on benchmark 2026

Fairness-Budgeted Short-Job Insertion

Replace unrestricted continuous batching with a fairness-constrained scheduler that only inserts a waiting request when its predicted decode footprint remains within a normalized distance of the longest request already in the batch. The fairness budget should be tuned away from the mathematically worst midpoint and validated against real arrival distributions, with the goal of reducing wasted max-driven decode work without falling back to inefficient one-request-at-a-time serving.

Useful7/10
Difficulty4/10
Novelty6/10
Paper: Efficiency and Cost Alignment in Batched LLM Serving via Resource-Fair Scheduling arXiv:2608.02244
△ Mechanism confirmed, baseline not beaten 2026

Dyadic Hankel Boundary Attention

Replace dense attention between tokens on opposite sides of a one-dimensional boundary or segment split with a dyadic low-rank approximation of a Cauchy/Hankel distance kernel. Each distance-scale block uses O(log(1/\varepsilon)) features, and the number of active scales grows only logarithmically with context length after discarding a narrow boundary layer. This is especially suitable for a relative-position attention branch or state-space-like long-range branch, rather than arbitrary…

Useful7/10
Difficulty5/10
Novelty6/10
Paper: An independent proof of the plunge-region conjecture for time-frequency localization operators in dimension one arXiv:2607.23016
✗ Failed on benchmark 2026

Balanced design attention

Construct overlapping attention windows from a block design instead of using one dense sequence-by-sequence attention matrix. Every token appears in exactly $r$ windows and every token pair co-occurs in exactly $\lambda$ windows, giving uniform coverage and avoiding the uneven connectivity of arbitrary sparse masks.

Useful7/10
Difficulty5/10
Novelty6/10
Paper: Block designs and systems of pairs arXiv:2607.18499
✗ Failed on benchmark 2026

Rank-Revealing Representative Tokens

Compress a transformer KV cache by selecting actual past tokens whose key or hidden-state columns form a stable basis for all cached tokens. Instead of retaining tokens with the largest attention scores or leverage scores independently, compute rank-revealing pivoting of the leading right-singular-vector matrix and retain its pivot columns, then evaluate attention using the representatives plus an optional low-cost residual correction.

Useful7/10
Difficulty5/10
Novelty6/10
Paper: Computing Strong Rank-Revealing Factorizations for Matrices with Orthonormal Rows arXiv:2607.13532
✗ Failed on benchmark 2026

Rotated Tucker residual for outlier-resistant KV quantization

Use a low-rank Tucker reconstruction as a structured backbone and quantize only its residual after an orthogonal rotation. The rotation preserves residual energy but redistributes it across coordinates, reducing dynamic-range imbalance and making 2- or 4-bit uniform quantization less damaging than direct quantization of the original KV tensor.

Useful7/10
Difficulty5/10
Novelty6/10
Paper: A JoLT for the KV cache: Near-lossless KV cache compression via joint Lagrangian allocation of Tucker ranks and a rotated residual for llms arXiv:2607.12550
△ Mechanism confirmed, baseline not beaten 2026

Residual-energy cross attention

Replace dense query-key attention with an adaptive cross approximation constructed from selected query and key pivot tokens. At each rank, choose the pivot pair that removes large estimated residual energy, update the residual by a rank-1 cross correction, and stop when the residual estimate reaches a target tolerance. The resulting factorization computes approximate attention using a small number of landmark interactions while adapting to the actual token distribution.

Useful7/10
Difficulty6/10
Novelty5/10
Paper: Continuous Cross Approximation of Matrices Arising Out of Kernel Functions arXiv:2607.12540
✗ Mechanism failed 2026

Subcritical Ancestral Attention

Construct a sparse attention layer by sampling backward token histories as a continuous-time branching process rather than allowing every query to attend to every key. Each active ancestor either dies or branches into a bounded number of candidate ancestors, with branching probability controlled by a small parameter. The branch-out penalty predicts exponentially small probability of long, highly branching histories, providing a direct knob for receptive-field size and attention FLOPs.

Useful7/10
Difficulty5/10
Novelty7/10
Paper: Cutoff with an $O(1)$ window for Potts Glauber Dynamics on lattice at High Temperature arXiv:2608.26259
Unverified 2026

Local-Tail Adaptive Attention

Replace a global attention truncation rule with a per-query local-tail budget. For each query token, retain nearby or high-priority keys until the estimated discarded interaction strength is below a target epsilon; this uses the paper's central distinction between local tail mass and the extensive norm of the discarded operator. The resulting attention pattern can allocate long-range computation only to tokens whose local tail is large.

Useful6/10
Difficulty5/10
Novelty5/10
Paper: Local observable errors from truncating interaction tails in gapped quantum lattice systems arXiv:2608.15576
Unverified 2026

Token-Count-Aware Attention Projection

Use the number of tokens participating in an attention operation to adapt the projected query/key dimension according to the sharp Johnson–Lindenstrauss bound. Short attention windows receive a dimension limited by n-1, while longer windows use a logarithmic dimension, avoiding a fixed large head dimension when the current attention set contains too few points to require it.

Useful6/10
Difficulty6/10
Novelty6/10
Paper: The Sharp Dimension Bound in the Johnson--Lindenstrauss Lemma arXiv:2608.13782
Unverified 2026

Prony-Compressed Temporal Memory

Approximate a long hidden-state or key/value trajectory by a small sum of exponential modes, storing only the mode nodes and vector weights instead of every timestep. Recover the modes from a Hankel matrix through an annihilating polynomial, then reconstruct the trajectory or a compact recurrent state during inference.

Useful6/10
Difficulty6/10
Novelty5/10
Paper: Contour Hankel dynamics and indicator fields for the Riemann $Ξ$-function arXiv:2608.11520
Unverified 2026

Residual-pivoted landmark attention

Replace uniform or random landmark selection in low-rank attention with approximate greedy pivoted QR selection on the attention matrix. At each step, select the key whose residual attention column has the largest norm, orthogonalize it against previously selected columns, and stop when the residual energy falls below a target tolerance. Use the selected columns as an adaptive attention basis and reconstruct the full attention output through a small coefficient matrix.

Useful6/10
Difficulty6/10
Novelty5/10
Paper: Convergence rates for pivoted QR and LU arXiv:2607.26863