Metamath Proof Explorer


Theorem elspansn5

Description: A vector belonging to both a subspace and the span of the singleton of a vector not in it must be zero. (Contributed by NM, 17-Dec-2004) (New usage is discouraged.)

Ref Expression
Assertion elspansn5 A S B ¬ B A C span B C A C = 0

Proof

Step Hyp Ref Expression
1 elspansn4 A S B C span B C 0 B A C A
2 1 biimprd A S B C span B C 0 C A B A
3 2 exp32 A S B C span B C 0 C A B A
4 3 com34 A S B C span B C A C 0 B A
5 4 imp32 A S B C span B C A C 0 B A
6 5 necon1bd A S B C span B C A ¬ B A C = 0
7 6 exp31 A S B C span B C A ¬ B A C = 0
8 7 com34 A S B ¬ B A C span B C A C = 0
9 8 imp4c A S B ¬ B A C span B C A C = 0