AsymptoticLessEqual

AsymptoticLessEqual[f,g,x->x*] gives conditions for f(x)⪯g(x) or f(x)∈O(g(x)) as x->x*.

AsymptoticLessEqual[f,g,{x1,…,xn}->{x1*,…,xn*}] gives conditions for f(x1,…,xn)⪯g(x1,…,xn) or f(x1,…,xn)∈O(g(x1,…,xn)) as {x1,…,xn}->{x1*,…,xn*}.

Please visit the official Wolfram Language Reference for more details and examples on core symbols.