On the Logical Dependence Between Sustained Attention and Working Memory

This preprint presents a formal conceptual analysis of the relationship between sustained attention and working memory. Using only canonical definitions from Cowan (working memory), Petersen & Posner (executive attention), and Huang et al. (sustained attention/vigilance), the paper derives a necessary conceptual dependence between the constructs. The argument is strictly logical and definitional in nature. No new frameworks are proposed, no empirical claims are made, and no claims of neural identity are advanced. The contribution concerns conceptual dependence rather than mechanistic equivalence.