LIR: Late Interaction Workshop @ ECIR 2026

Overview

The LIR Workshop is the first academic workshop dedicated to late interaction and multi-vector retrieval methods, held at ECIR 2026 in Delft, Netherlands on April 2, 2026.

Schedule

• Date: April 2, 2026
• Time: 09:00-13:00 (Half-day workshop)
• Location: Delft, Netherlands (ECIR 2026 Workshop Day)

Workshop Format

• Keynote presentation
• Paper sessions
• Demo presentations
• Roundtable discussion

Keynote Speaker

Omar Khattab, Assistant Professor at MIT, whose research pioneered modern multi-vector retrieval including:

• ColBERT (original approach)
• ColBERTv2 (improved version)
• PLAID indexing method (de facto standard)

Topics of Interest

Core Topics

• Late interaction retrieval methods
• Multi-vector representations
• Token-level similarity matching
• Fine-grained document representations

Advanced Research Areas

1. Training and Optimization

   • Impact of different scheduling strategies
   • Data mix optimization for late-interaction models
   • Training loss functions
   • Model-specific improvements

2. Multi-Modal Retrieval

   • ColPali for document understanding
   • VideoColBERT for video search
   • Modality-specific approaches
   • Cross-modal late interaction

3. Long-Context and Agentic Tasks

   • Long-context retrieval challenges
   • Agentic Search systems
   • Deep Research tasks
   • Reasoning-based retrieval

Why Late Interaction Matters

Late interaction methods, pioneered by ColBERT, have emerged as a powerful alternative to single-vector neural IR by:

• Leveraging fine-grained, token-level representations
• Delivering strong generalization
• Providing robust out-of-domain performance
• Enabling explainable similarity matching

Recent Advances

• Early multimodal work suggests late-interaction models suit most modalities
• ColPali and VideoColBERT showing promising results
• Outperforming other retriever families in specific domains
• Unified frameworks emerging for different modalities

Community Impact

The workshop addresses:

• Fragmentation across research communities
• Integration of practitioner perspectives
• Rapid advances in multiple research areas
• Need for standardized evaluation

Call for Papers

Welcoming submissions on:

• Novel late-interaction architectures
• Efficiency improvements
• Multi-modal extensions
• Real-world deployment experiences
• Benchmark and evaluation studies

Relevance to Industry

Late interaction models are increasingly being adopted in production systems for:

• Document retrieval without preprocessing
• Visual question answering
• Multi-modal search applications
• Context-preserving similarity matching