Pooling reduces the size of learned representations so later learning tasks can work with a smaller output. In graph neural networks, it is mainly used to turn node-level outputs into representations for graph-level prediction. section 3.4.1 section 3.4.2
Use pooling as the size-reduction stage after feature transformation and activation:
- A convolution or message-passing operation transforms local graph information into learned representations. section 3.4.1 section 3.4.2
- An activation function adds the nonlinear transformation needed for a multilayer model to remain more expressive than a linear model. section 3.4.2
- Pooling then reduces the overall output size for graph-level tasks; node-prediction workflows can omit it. section 3.4.2
Grid and graph intuition
In a CNN, a layer follows the pattern filter → activation function → pooling, reducing an image-derived representation for downstream classification. A GNN applies the analogous reduction after graph convolution or message passing when the target is a whole graph rather than an individual node. section 3.4.1 section 3.4.2







