Metamath Proof Explorer


Theorem opprlemOLD

Description: Obsolete version of opprlem as of 6-Nov-2024. Lemma for opprbas and oppradd . (Contributed by Mario Carneiro, 1-Dec-2014) (New usage is discouraged.) (Proof modification is discouraged.)

Ref Expression
Hypotheses opprbas.1 O = opp r R
opprlemOLD.2 E = Slot N
opprlemOLD.3 N
opprlemOLD.4 N < 3
Assertion opprlemOLD E R = E O

Proof

Step Hyp Ref Expression
1 opprbas.1 O = opp r R
2 opprlemOLD.2 E = Slot N
3 opprlemOLD.3 N
4 opprlemOLD.4 N < 3
5 2 3 ndxid E = Slot E ndx
6 3 nnrei N
7 6 4 ltneii N 3
8 2 3 ndxarg E ndx = N
9 mulrndx ndx = 3
10 8 9 neeq12i E ndx ndx N 3
11 7 10 mpbir E ndx ndx
12 5 11 setsnid E R = E R sSet ndx tpos R
13 eqid Base R = Base R
14 eqid R = R
15 13 14 1 opprval O = R sSet ndx tpos R
16 15 fveq2i E O = E R sSet ndx tpos R
17 12 16 eqtr4i E R = E O