qmax

Qmax is a notation used in various fields to denote the maximum value of a quantity q within a defined context. It is not a universal constant; its exact meaning depends on the domain and on how it is defined in a given source.

In mathematics and optimization, qmax commonly represents the maximum or supremum of a function q over a domain D, i.e., qmax = max{ q(x) : x ∈ D } or qmax = sup{ q(x) : x ∈ D } if the maximum is not attained. It often appears in constrained optimization and in definitions of upper bounds.

In reinforcement learning and related machine learning literature, q often denotes an action-value function Q. qmax can denote the maximum action-value for a state s, qmax(s) = max_a Q(s,a). This represents the best possible value achievable by choosing the optimal action in that state.

In other contexts, qmax can denote a theoretical upper bound or capacity in queueing theory, networking, or electronics, e.g., maximum queue length Qmax or maximum charge Qmax. The exact interpretation depends on the document and must be defined in context.

Because qmax is not a fixed standard symbol, readers should consult the definitions provided in each source.