Past exam of the mathematics course of the University of Cambridge 2004 ia Paper 1 8C ii Solution Created 2026-09-24 Updated 2026-10-14
No. For every , takein . These form a minimally dependent vector family: the full family is dependent because .
If the omitted vector is , the remaining coordinate vectors are independent. If the omitted vector is , a relation among the retained vectors has an coordinate coming only from , so its coefficient must be zero; the coefficients of all retained coordinate vectors must then be zero. Thus every -element subfamily is linearly independent, as required for a counterexample. When , the empty subfamily is independent while the one-vector family consisting of the zero vector is not, so the answer remains negative.