• Equivariance and Invariance. Equivariance refers to a system's ability that the output changes in a predictable way when the input is transformed. For example, electron density mapping will rotate in alignment with the atom coordinates' rotation. Invariance means that the output of the model remains unchanged even when the input undergoes certain transformations. This is crucial for predicting global features (such as enzyme class, property, or function) that should remain constant regardless of the orientation or position of the structure. Both equivariance and invariance are important for the recognition and understanding of microscopic structures .