Forward box minus
From timescalewiki
Let $\mathbb{T}$ be a time scale. We define the (forward) boxminus operation $\boxminus_{\mu}$ by $$\left( p \boxplus_{\mu} q \right)(t) := \dfrac{t\Big(p(t)-q(t)\Big)}{t+g(t)\mu(t)},$$ where $\mu$ denotes the forward graininess.
See also
Forward boxplus
Gamma function