# Tag Info

There are two directions. When you're asking for help with an "if and only if" problem, 99% of the time you should say which direction you're having trouble with (and usually, you should be even more specific than that). Starting with an isomorphism, to find a change of basis: First of all, an isomorphism $(V_1,T_1)\to(V_2,T_2)$ is a function $V_1\to V_2$ ...