Open Research Problems in Graph ML

I thought I would make my first subscriber-only post on the open research problems in graph ML. These are the problems that I have thought a lot and think can have a transformational impact not only on this field, but also on the applications of graph models to other areas.

Fresh picks from ArXiv
This week on ArXiv: new heterophily datasets, improved inference and expressive power for GNNs 🦹‍

If I forgot to mention your paper, please shoot me a message and I will update the post.

GNNs
* New Benchmarks for Learning on Non-Homophilous Graphs
* Adaptive Filters and Aggregator Fusion for Efficient Graph Convolutions with Pietro Liò
* Improving the Expressive Power of Graph Neural Network with Tinhofer Algorithm
* Sub-GMN: The Subgraph Matching Network Model
* SST-GNN: Simplified Spatio-temporal Traffic forecasting model using Graph Neural Network

Math
* Using Graph Theory to Derive Inequalities for the Bell Numbers

Software
* LAGraph: Linear Algebra, Network Analysis Libraries, and the Study of Graph Algorithms

Survey
* Scene Graphs: A Survey of Generations and Applications

Topological GNNs and graph models for video

Two articles recently were featured on Synced. One is Making GNNs ‘Topology-Aware’ to Advance their Expressive Power about using persistent homology for additional expressivity of GNNs. Another is SOTA GNN ‘Reasons’ Interactions over Time to Boost Video Understanding about modeling images as graphs to reason about their content.

Adaptive Filters and Aggregator Fusion for Efficient Graph Convolutions

A blog post by Shyam A. Tailor about a simple modification of GCN layer that is both more efficient and more effective than many standard message-passing algorithms.

The London Geometry and Machine Learning Summer School 2021

A very cool one week school on geometric deep learning, happening online this summer. Early career researchers such as Ph.D. students will work in small groups under the guidance of experienced mentors on a research project. Applications are open until 31 May 2021.

Bag of Tricks for Semi-Supervised classification

There is a nice short paper on tricks employed on improving performance of GNN. The author, Yangkun Wang, from DGL team has a lot of high scoring entries in the OGB leaderboard, so it's worth employing these tricks: they boost performance a bit but do it consistently. The tricks include:

* data augmentation
* using labels as node features
* renormalization of adjacency matrix
* novel loss functions
* residual connections from the input

Mathematicians Settle Erdős Coloring Conjecture

Erdős-Faber-Lovász conjecture states that the minimum number of colors necessary to shade the edges of a hypergraphs so that no overlapping edges have the same color is bounded by the number of vertices. After 50 years of research it has finally been resolved.

Fresh picks from ArXiv
This week on ArXiv: improved power of GNNs, new autoML library for graphs, and decreasing query time for graph traversal 🕔

If I forgot to mention your paper, please shoot me a message and I will update the post.

GNNs
* Theoretically Improving Graph Neural Networks via Anonymous Walk Graph Kernels
* A Graph VAE and Graph Transformer Approach to Generating Molecular Graphs
* Learning to Coordinate via Multiple Graph Neural Networks
* DyGCN: Dynamic Graph Embedding with Graph Convolutional Network
* Hyperbolic Variational Graph Neural Network for Modeling Dynamic Graphs with Philip S. Yu
* The World as a Graph: Improving El Niño Forecasts with Graph Neural Networks

kNN
* Graph Reordering for Cache-Efficient Near Neighbor Search with Alex Smola

Software
* AutoGL: A Library for Automated Graph Learning

Survey
* Representation Learning for Networks in Biology and Medicine: Advancements, Challenges, and Opportunities with Marinka Zitnik

Outlier detection and description workshop at KDD 2021

Graph methods are very popular in detecting fraud as they are capable to distinguish interactions of fraudsters from benign users. There is a big workshop at KDD 2021 about detecting and describing outliers, with a great list of keynote speakers.

Weisfeiler and Lehman Go Topological: Message Passing Simplical Networks

A video presentation (and slides) by Cristian Bodnar & Fabrizio Frasca on a new type of GNNs that defines neighborhoods based on the simplical complexes of a graph. It goes quite deep into the theory with the supporting experiments in graph isomorphism, graph classification, and trajectory disambiguation.

Videos from CS224W

A legendary Stanford CS224W course on graph ML now releases videos on YouTube for 2021. Promised to be 2 lectures each week. Slides available on the site too (homeworks are still missing).

Fresh picks from ArXiv
This week on ArXiv: equivalence of graph matching and GED, hyperbolic GNNs, and de-anon of blockchain 💲

If I forgot to mention your paper, please shoot me a message and I will update the post.

GNNs
* Reinforced Neighborhood Selection Guided Multi-Relational Graph Neural Networks with Philip S. Yu
* Higher-Order Attribute-Enhancing Heterogeneous Graph Neural Networks with Philip S. Yu
* Generative Causal Explanations for Graph Neural Networks
* DistGNN: Scalable Distributed Training for Large-Scale Graph Neural Networks
* Identity Inference on Blockchain using Graph Neural Network

Conferences
* MEG: Generating Molecular Counterfactual Explanations for Deep Graph Networks IJCNN 2021
* FedGraphNN: A Federated Learning System and Benchmark for Graph Neural Networks MLSys Workshop 2021
* Search to aggregate neighborhood for graph neural network ICDE 2021

Hyperbolic
* A Hyperbolic-to-Hyperbolic Graph Convolutional Network
* Lorentzian Graph Convolutional Networks

Math
* On the unification of the graph edit distance and graph matching problems

Self-supervised learning of GNNs

Self-supervised learning (SSL) is a paradigm of learning when we have large amounts unlabeled data and we want to get representation of the input which we can use later for the downstream tasks. The difference between unsupervised and self-supervised learning is that unsupervised learning attempts to learn a representation on a single input, while SSL assumes there is a model trained across several inputs.

Examples of unsupervised learning on graphs is graph kernels that boil down to counting some statistics on graphs (e.g. motifs) which would represent a graph. Examples of SSL is when you first create multiple views of the same graph (e.g. by permuting the edges) and then train a model to distinguish views of different graphs. DeepWalk, node2vec and other pre-GNN node embeddings are somewhere in between: they are usually applied to a single graph, but the concept could be well applied to learning representations on many graphs as well.

There is a recent boom in this area for graphs, so there are some fresh surveys available (here and here) as well as the awesome list of SSL-GNNs.

Awesome graph repos

Collections of methods and papers for specific graph topics.

Graph-based Deep Learning Literature — Links to Conference Publications and the top 10 most-cited publications, Related workshops, Surveys / Literature Reviews / Books in graph-based deep learning.

awesome-graph-classification — A collection of graph classification methods, covering embedding, deep learning, graph kernel and factorization papers with reference implementations.

Awesome-Graph-Neural-Networks — A collection of resources related with graph neural networks..

awesome-graph — A curated list of resources for graph databases and graph computing tools

awesome-knowledge-graph — A curated list of Knowledge Graph related learning materials, databases, tools and other resources.

awesome-knowledge-graph — A curated list of awesome knowledge graph tutorials, projects and communities.

Awesome-GNN-Recommendation — graph mining for recommender systems.

awesome-graph-attack-papers — links to works about adversarial attacks and defenses on graph data or GNNs.

Graph-Adversarial-Learning — Attack-related papers, Defense-related papers, Robustness Certification papers, etc., ranging from 2017 to 2021.

awesome-self-supervised-gnn — Papers about self-supervised learning on GNNs.

awesome-self-supervised-learning-for-graphs — A curated list for awesome self-supervised graph representation learning resources.

Awesome-Graph-Contrastive-Learning — Collection of resources related with Graph Contrastive Learning.

Graph Machine Learning research groups: Leman Akoglu

I do a series of posts on the groups in graph research, previous post is here. The 27th is Leman Akoglu, a professor at the Carnegie Mellon University, with interests in detecting anomalies in graphs.

Leman Akoglu (~1983)
- Affiliation: Carnegie Mellon University
- Education: Ph.D. at Duke University in 2012 (advisors: Christos Faloutsos)
- h-index 40
- Interests: anomaly detection, graph neural networks
- Awards: best research papers at PAKDD, SIAM SDD, ECML PKDD

Graph Neural Networks in Computational Biology

Slides from Petar Veličković about his journey on using machine learning algorithms on biological data.

Fresh picks from ArXiv
This week on ArXiv: accelerated inference for GNNs, graph MLP and graph-augmented sponsored search 🔍

If I forgot to mention your paper, please shoot me a message and I will update the post.

GNNs
* Learnable Online Graph Representations for 3D Multi-Object Tracking
* GMLP: Building Scalable and Flexible Graph Neural Networks with Feature-Message Passing
* Accelerating SpMM Kernel with Cache-First Edge Sampling for Graph Neural Networks

Conferences
* Efficient Relation-aware Scoring Function Search for Knowledge Graph Embedding ICDE 2021
* Temporal Knowledge Graph Reasoning Based on Evolutional Representation Learning SIGIR 2021
* AdsGNN: Behavior-Graph Augmented Relevance Modeling in Sponsored Search SIGIR 2021

GNN User Group: meeting 4

Fourth meeting of GNN user group will include talks from me (Sergey Ivanov) where I will talk about combination of GBDT and GNNs, and professor Pan Li from Purdue University who will speak about constructing structural features to improve representations in temporal networks. Please join us on Thusday!

Videos from WebConf 2021

Videos from WebConf 2021 are available here. Many graph talks on topics such as GNN, graph models, knowledge graphs, graph embeddings, link prediction, and more.

Geometric Deep Learning Book

A new book by graph ML experts Michael M. Bronstein, Joan Bruna, Taco Cohen, and Petar Veličković on geometric deep learning is released. 156 pages on exploring symmetries that unifies different ML neural network architectures. An accompanying post nicely introduces the history of the geometry and its impact on the physics. It's exciting to see a categorization of many ML approaches from the perspective of the group theory.