Metamath Proof Explorer

Theorem outsidene1

Description: Outsideness implies inequality. (Contributed by Scott Fenton, 18-Oct-2013) (Revised by Mario Carneiro, 19-Apr-2014)

		Ref	Expression
	Assertion	outsidene1	\|- ( ( N e. NN /\ ( P e. ( EE ` N ) /\ A e. ( EE ` N ) /\ B e. ( EE ` N ) ) ) -> ( P OutsideOf <. A , B >. -> A =/= P ) )

Proof

Step	Hyp	Ref	Expression
1		broutsideof2	\|- ( ( N e. NN /\ ( P e. ( EE ` N ) /\ A e. ( EE ` N ) /\ B e. ( EE ` N ) ) ) -> ( P OutsideOf <. A , B >. <-> ( A =/= P /\ B =/= P /\ ( A Btwn <. P , B >. \/ B Btwn <. P , A >. ) ) ) )
2		simp1	\|- ( ( A =/= P /\ B =/= P /\ ( A Btwn <. P , B >. \/ B Btwn <. P , A >. ) ) -> A =/= P )
3	1 2	syl6bi	\|- ( ( N e. NN /\ ( P e. ( EE ` N ) /\ A e. ( EE ` N ) /\ B e. ( EE ` N ) ) ) -> ( P OutsideOf <. A , B >. -> A =/= P ) )

Step

Hyp

Ref

Expression

broutsideof2

 |-  ( ( N e. NN /\ ( P e. ( EE ` N ) /\ A e. ( EE ` N ) /\ B e. ( EE ` N ) ) ) -> ( P OutsideOf <. A , B >. <-> ( A =/= P /\ B =/= P /\ ( A Btwn <. P , B >. \/ B Btwn <. P , A >. ) ) ) )

simp1

 |-  ( ( A =/= P /\ B =/= P /\ ( A Btwn <. P , B >. \/ B Btwn <. P , A >. ) ) -> A =/= P )

1 2

syl6bi

 |-  ( ( N e. NN /\ ( P e. ( EE ` N ) /\ A e. ( EE ` N ) /\ B e. ( EE ` N ) ) ) -> ( P OutsideOf <. A , B >. -> A =/= P ) )