I refer to the Wikipedia and other tutorials on topic modeling, which said
although PLSA is a generative model of the documents in the collection it is estimated on, it is not a generative model of new documents.
while another tutorial page 15 that illustrates pLSA and LDA in geometric way said
The pLSI model allows a document to possess a distribution over topics that was seen in the training data, thus placing new documents at particular points within the topic simplex.
Could I and should I use a trained pLSA model to generate topic distributions on unseen (new) documents?