Metamath Proof Explorer


Theorem lsatn0

Description: A 1-dim subspace (atom) of a left module or left vector space is nonzero. ( atne0 analog.) (Contributed by NM, 25-Aug-2014)

Ref Expression
Hypotheses lsatn0.o 0 = ( 0g𝑊 )
lsatn0.a 𝐴 = ( LSAtoms ‘ 𝑊 )
lsatn0.w ( 𝜑𝑊 ∈ LMod )
lsatn0.u ( 𝜑𝑈𝐴 )
Assertion lsatn0 ( 𝜑𝑈 ≠ { 0 } )

Proof

Step Hyp Ref Expression
1 lsatn0.o 0 = ( 0g𝑊 )
2 lsatn0.a 𝐴 = ( LSAtoms ‘ 𝑊 )
3 lsatn0.w ( 𝜑𝑊 ∈ LMod )
4 lsatn0.u ( 𝜑𝑈𝐴 )
5 eqid ( Base ‘ 𝑊 ) = ( Base ‘ 𝑊 )
6 eqid ( LSpan ‘ 𝑊 ) = ( LSpan ‘ 𝑊 )
7 5 6 1 2 islsat ( 𝑊 ∈ LMod → ( 𝑈𝐴 ↔ ∃ 𝑣 ∈ ( ( Base ‘ 𝑊 ) ∖ { 0 } ) 𝑈 = ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) ) )
8 3 7 syl ( 𝜑 → ( 𝑈𝐴 ↔ ∃ 𝑣 ∈ ( ( Base ‘ 𝑊 ) ∖ { 0 } ) 𝑈 = ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) ) )
9 4 8 mpbid ( 𝜑 → ∃ 𝑣 ∈ ( ( Base ‘ 𝑊 ) ∖ { 0 } ) 𝑈 = ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) )
10 eldifsn ( 𝑣 ∈ ( ( Base ‘ 𝑊 ) ∖ { 0 } ) ↔ ( 𝑣 ∈ ( Base ‘ 𝑊 ) ∧ 𝑣0 ) )
11 5 1 6 lspsneq0 ( ( 𝑊 ∈ LMod ∧ 𝑣 ∈ ( Base ‘ 𝑊 ) ) → ( ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) = { 0 } ↔ 𝑣 = 0 ) )
12 3 11 sylan ( ( 𝜑𝑣 ∈ ( Base ‘ 𝑊 ) ) → ( ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) = { 0 } ↔ 𝑣 = 0 ) )
13 12 biimpd ( ( 𝜑𝑣 ∈ ( Base ‘ 𝑊 ) ) → ( ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) = { 0 } → 𝑣 = 0 ) )
14 13 necon3d ( ( 𝜑𝑣 ∈ ( Base ‘ 𝑊 ) ) → ( 𝑣0 → ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) ≠ { 0 } ) )
15 14 expimpd ( 𝜑 → ( ( 𝑣 ∈ ( Base ‘ 𝑊 ) ∧ 𝑣0 ) → ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) ≠ { 0 } ) )
16 10 15 syl5bi ( 𝜑 → ( 𝑣 ∈ ( ( Base ‘ 𝑊 ) ∖ { 0 } ) → ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) ≠ { 0 } ) )
17 neeq1 ( 𝑈 = ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) → ( 𝑈 ≠ { 0 } ↔ ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) ≠ { 0 } ) )
18 17 biimprcd ( ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) ≠ { 0 } → ( 𝑈 = ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) → 𝑈 ≠ { 0 } ) )
19 16 18 syl6 ( 𝜑 → ( 𝑣 ∈ ( ( Base ‘ 𝑊 ) ∖ { 0 } ) → ( 𝑈 = ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) → 𝑈 ≠ { 0 } ) ) )
20 19 rexlimdv ( 𝜑 → ( ∃ 𝑣 ∈ ( ( Base ‘ 𝑊 ) ∖ { 0 } ) 𝑈 = ( ( LSpan ‘ 𝑊 ) ‘ { 𝑣 } ) → 𝑈 ≠ { 0 } ) )
21 9 20 mpd ( 𝜑𝑈 ≠ { 0 } )