Sentence:  Caswell (1989) pointed out that most linear stage-structured models have both primitive and irreducible <WSD>projection matrices</WSD>....The <WSD>projection matrix</WSD> <WSD>M</WSD> shown in the table is then calculated as PS + <WSD>R</WSD>. 
Meaning of the word marked with <WSD> tags:  A matrix that maps a vector of response (dependent variable) values to a vector of fitted or predicted values.