Second hint

Second hint

I feel like a second hint would be good here. Maybe writing A = {a_1, a_2, ...} and/or to clarify that B \subsetneq A and |A| = |B| are not a contradiction for infinite sets.

Bernhard Konrad (talk)21:45, 5 May 2015

I think the second is unnecessary (I hope by now in this course students have realized that infinity and one less than infinity are still both infinite.

CarmenBruni (talk)02:32, 7 May 2015

You're right. The new second hint is helpful.

Bernhard Konrad (talk)04:00, 7 May 2015