GraphTheory/IsHamiltonian says that the method can be one of legacy, sat, or tsp. But why method = tsp brings about an error? 

GraphTheory:-IsHamiltonian(GraphTheory:-CompleteGraph(3, 3), method = tsp); # Maple 2022.2

Attachment: HamiltonianGraphQ.mws

Let x, y, z be nonnegative real numbers. Obviously, x³+y³+z³-4xyz is not always nonnegative, since its value is -1 when x=y=z=1. But why Maple's minimize gives wrong result? 

minimize(x^3 + y^3 + z^3 - 4*x*y*z, x = 0 .. infinity, y = 0 .. infinity, z = 0 .. infinity);

Attachment: MinValue.mws.

MMA's Minimize finds correct infimum: 
So, can Maple always find correct exact (i.e., not just numerical) global minima (or maxima) at least for such problems with a small number of variables as well?