“…(ii) if 𝑓 (x) ≡ Const; g(x) ≡ 0; s(x) ≡ 0; h ≡ 1, then the corresponding W was studied in Ganikhodzhaev and Zanin 31 (iii) if g(x) ≡ 0, s(x) ≡ 0 and 𝑓 (x) is a quadratic polynomial with h ≡ 1, then the corresponding W has been studied in previous studies 24,27,32,33 ; (iv) if s(x) ≡ 0, 𝑓(x), g(x) and h are arbitrary, then the corresponding W has been studied in Saburov 1 ; (v) if the dimension of the simplex is more than 2, then particular cases of W have been investigated in previous studies. 23,25,34 Example 2.3. Assume that 𝑓 (x) ∶ [0, 1] → [0, 1] is an increasing continuous function.…”