Now this may seem like a silly (or even stupid) thing to say so carefully. Ofcourse two vectors are equal if they are equal for each corresponding entry! Well,this is not as silly as it appears. We will see a few occasions later where the obviousdefinition is not the right one. And besides, in doing mathematics we need to be verycareful about making all the necessary definitions and making them unambiguous.And we have done that here.Notice now that the symbol “=” is now doing triple-duty. We know from ourearlier education what it means for two numbers (real or complex) to be equal, andwe take this for granted. In Definition SE we defined what it meant for two setsto be equal. Now we have defined what it means for two vectors to be equal, andthat definition builds on our definition for when two numbers are equal when weuse the condition ui = vi for all 1 ≤ i ≤ m. So think carefully about your objectswhen you see an equal sign and think about just which notion of equality you haveencountered. This will be especially important when you are asked to constructproofs whose conclusion states that two objects are equal. If you have an electroniccopy of the book, such as the PDF version, searching on “Definition CVE” can bean instructive exercise. See how often, and where, the definition is employed.OK, let us do an example of vector equality that begins to hint at the utility ofthis definition