Metamath Proof Explorer


Theorem sn-ltaddpos

Description: ltaddpos without ax-mulcom . (Contributed by SN, 13-Feb-2024)

Ref Expression
Assertion sn-ltaddpos
|- ( ( A e. RR /\ B e. RR ) -> ( 0 < A <-> B < ( B + A ) ) )

Proof

Step Hyp Ref Expression
1 0re
 |-  0 e. RR
2 ltadd2
 |-  ( ( 0 e. RR /\ A e. RR /\ B e. RR ) -> ( 0 < A <-> ( B + 0 ) < ( B + A ) ) )
3 1 2 mp3an1
 |-  ( ( A e. RR /\ B e. RR ) -> ( 0 < A <-> ( B + 0 ) < ( B + A ) ) )
4 readdid1
 |-  ( B e. RR -> ( B + 0 ) = B )
5 4 adantl
 |-  ( ( A e. RR /\ B e. RR ) -> ( B + 0 ) = B )
6 5 breq1d
 |-  ( ( A e. RR /\ B e. RR ) -> ( ( B + 0 ) < ( B + A ) <-> B < ( B + A ) ) )
7 3 6 bitrd
 |-  ( ( A e. RR /\ B e. RR ) -> ( 0 < A <-> B < ( B + A ) ) )