((join R') (M ((join R') (M ρ) γ)) φ) = ((join R') (M ρ) (join G') (M γ) φ)
which by the distributivity of functors over composition, and helping ourselves to associativity on the lhs, yields:
((join R') (M ((join R') (M ρ) γ)) φ) = ((join R') (M ρ) (join G') (M γ) φ)
which by the distributivity of functors over composition, and helping ourselves to associativity on the lhs, yields: