Man pages matching name pdl::graphics::trid::mathgraph in section 3pm:

PDL::Graphics::TriD::MathGraph.3pm.en	debian 10 / pdl
PDL::Graphics::TriD::MathGraph.3pm.en	debian 11 / pdl
PDL::Graphics::TriD::MathGraph.3pm.en	debian 12 / pdl
PDL::Graphics::TriD::MathGraph.3pm.en	debian 13 / libpdl-graphics-trid-perl