+ An operator is Lyapunov-like on a cone if and only if both the
+ operator and its negation are cross-positive on the cone::
+
+ sage: K = random_cone(max_ambient_dim=5)
+ sage: R = K.lattice().vector_space().base_ring()
+ sage: L = random_matrix(R, K.lattice_dim())
+ sage: actual = is_lyapunov_like_on(L,K) # long time
+ sage: expected = (is_cross_positive_on(L,K) and # long time
+ ....: is_cross_positive_on(-L,K)) # long time
+ sage: actual == expected # long time
+ True
+