monotone-ops 0.1.1.dev1

Research-oriented monotone operator catalog for deterministic aggregation, CRDTs, fixpoints, and algebraic dataflow.

monotone-ops

A typed Python catalog of monotone operators for deterministic aggregation, evidence rollups, CRDT state joins, abstract interpretation, positive relational/dataflow rules, semiring path problems, information lattices, and security/risk labels.

The package is intentionally small and dependency-free at runtime. It provides reusable operators for experiments that need explicit order semantics, deterministic joins, finite law checks, or fixpoint-style closure.

monotone-ops supports Python 3.10 through 3.12.

Features

• Defines typed unary, binary, and order protocols for monotone operator experiments.
• Includes finite law checks for associativity, commutativity, idempotence, and monotonicity.
• Covers Boolean, numeric, ordering, collection, sequence, information, interval, graph, relational, semiring, probability, evidence, CRDT, security, and Galois-style domains.
• Provides examples for evidence rollups and semiring path problems.
• Ships py.typed so downstream packages can type-check imports from monotone_ops.

Installation

uv

uv add monotone-ops

pip

pip install monotone-ops

Usage

The package module is monotone_ops.

from monotone_ops.core import fold
from monotone_ops.collections import set_union
from monotone_ops.numeric import saturating_sum

facts = fold(set_union, [frozenset({"a"}), frozenset({"b"})])
score = fold(saturating_sum(10), [3, 4, 9])

assert facts == frozenset({"a", "b"})
assert score == 10

Development

uv run --directory pkgs --package monotone-ops ruff format experimental/monotone_ops
uv run --directory pkgs --package monotone-ops ruff check experimental/monotone_ops --fix
uv run --directory pkgs --package monotone-ops pytest experimental/monotone_ops/tests

Operator categories

Module	Category	Examples
core	protocols, folds, orders	Binary, Leq, fold, scan, dual, product_leq
laws	finite law checks	associativity, commutativity, idempotence, monotonicity
boolean	positive Boolean functions	OR, AND, k-of-n, majority, monotone CNF/DNF
numeric	numeric monotone maps	max, min, nonnegative sum/product, saturation, clamp, positive linear maps
ordering	order-induced selectors	argmax, argmin, lexicographic max/min, Pareto antichain join
collections	set/map/tuple/counter/bitset	union, intersection, dict pointwise join/meet, counter max/min
sequence	prefix/subsequence orders	append, longest common prefix, ordered dedup union, scans
information	knowledge lattices	unknown/known/conflict join, record joins, provenance support
intervals	abstract interval domain	hull join, intersection meet, interval arithmetic, widening/narrowing
abstract	small abstract domains	sign lattice, taint lattice, finite powerset abstraction
fixedpoint	closure/fixpoint iteration	least fixpoint, inflationary fixpoint, set closure, positive rule closure
galois	adjunction-derived operators	closure/interior operators, Moore closure, Alexandrov interior
graph	graph inclusion operators	graph union, reachability, transitive closure, components
relational	positive relational algebra	union, selection, projection, natural join, positive consequence
semiring	algebraic path operators	Boolean, tropical, max-plus, max-min, Viterbi, Floyd-Warshall closure
matrix	entrywise/grid operators	entrywise max/min/add, monotone dilation/erosion
probability	confidence/evidence scoring	max confidence, noisy-or, logaddexp, bounded evidence sum
evidence	quorum/certification	quorum state, weighted evidence, claim support, scorecards
crdt	state-based CRDT joins	G-Set, 2P-Set, G-Counter, PN-Counter, LWW register, OR-Set, vector clock
security	labels and policy lattices	restrictive decision join, permission bitsets, risk max, trust min

Design rule

An operator in this package is included when it is monotone under an explicit order. Operators that are also associative, commutative, and idempotent are suitable for order-independent streaming merges. Operators such as nonnegative sum or logaddexp are monotone and associative mathematically, but not idempotent; use them for evidence accumulation rather than CRDT-style state joins.

Clamping operators normalize state. For example, capped_max(Bounds(0, 1)) is idempotent on already-clamped values; outside that domain it first maps values into the bounded lattice.

Research anchors

This catalog is organized around established monotone structures:

• Lattices, joins, meets, closure/interior operators, and Tarski-style fixed points.
• CRDT state convergence via monotonic semilattices and least-upper-bound merge.
• Abstract interpretation via ordered abstract domains, joins, widenings, and fixpoint approximation.
• Positive relational algebra and Datalog-style immediate-consequence operators.
• Semiring frameworks for generic shortest-distance and algebraic path problems.

Primary references used while shaping the catalog:

• Shapiro et al., Conflict-Free Replicated Data Types, 2011.
• Cousot and Cousot, Abstract Interpretation: A Unified Lattice Model, POPL 1977.
• Tarski fixed point theorem lecture notes, EPFL/LARA.
• Nutt, Datalog with Negation, Foundations of Database Systems lecture notes.
• Mohri, Semiring Frameworks and Algorithms for Shortest-Distance Problems.
• Astral uv documentation for project and build-backend structure.