  We study top-tagging from an analytical QCD perspective focusing on the role
of two key steps therein : a step to find three-pronged substructure and a step
that places constraints on radiation. For the former we use a recently
introduced modification of Y-Splitter, known as Y$_{\text{m}}$-Splitter, and
for the latter we use the well-known N-subjettiness variable. We derive
resummed results for this combination of variables for both signal jets and
background jets, also including pre-grooming of the jet. Our results give new
insight into the performance of top tagging tools in particular with regard to
the role of the distinct steps involved.
