/**
 * Pure deduplication detection utilities.
 *
 * These functions operate on plain data (arrays, sets, strings) with no
 * infrastructure dependencies. They can be used by both the infrastructure
 * DeduplicationService and skill-level MemoryService.
 */
import type { IMemoryItem } from '../interfaces/types';
import type { IConflictGroup } from '../interfaces/dal/types';
import type { IDuplicateGroup, IDeduplicationOptions } from '../interfaces/IDeduplicationService';
/**
 * Normalize text for comparison: lowercase, trim, collapse whitespace.
 */
export declare function normalizeText(text: string): string;
/**
 * Extract meaningful words from text, removing stop words.
 * Returns a set of lowercase words.
 */
export declare function extractWords(text: string): Set<string>;
/**
 * Compute Jaccard similarity between two word sets.
 * Returns |A ∩ B| / |A ∪ B|, or 0 if both sets are empty.
 */
export declare function jaccardSimilarity(a: Set<string>, b: Set<string>): number;
/**
 * Detect duplicates from a pre-loaded array of facts.
 *
 * Three-pass algorithm:
 * 1. Exact match — identical normalized text
 * 2. Tag overlap — same type:* tag with shared words (via conflict groups)
 * 3. Similar content — Jaccard word-set similarity
 *
 * @param facts - Array of memory items to scan
 * @param conflictGroups - Pre-fetched conflict groups (for tag overlap pass)
 * @param options - Detection options
 */
export declare function detectDuplicatesFromFacts(facts: readonly IMemoryItem[], conflictGroups: readonly IConflictGroup[], options?: IDeduplicationOptions): IDuplicateGroup[];
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