∀ {M : Type u} {N : Type u_2} [inst : Mul M] [inst_1 : PseudoEMetricSpace M] [IsIsometricSMul Mᵐᵒᵖ M] [inst_3 : Mul N]
  [inst_4 : PseudoEMetricSpace N] [IsIsometricSMul Nᵐᵒᵖ N], IsIsometricSMul (M × N)ᵐᵒᵖ (M × N)