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Theorem infeq2 6950
Description: Equality theorem for infimum. (Contributed by AV, 2-Sep-2020.)
Assertion
Ref Expression
infeq2  |-  ( B  =  C  -> inf ( A ,  B ,  R
)  = inf ( A ,  C ,  R
) )

Proof of Theorem infeq2
StepHypRef Expression
1 supeq2 6925 . 2  |-  ( B  =  C  ->  sup ( A ,  B ,  `' R )  =  sup ( A ,  C ,  `' R ) )
2 df-inf 6921 . 2  |- inf ( A ,  B ,  R
)  =  sup ( A ,  B ,  `' R )
3 df-inf 6921 . 2  |- inf ( A ,  C ,  R
)  =  sup ( A ,  C ,  `' R )
41, 2, 33eqtr4g 2215 1  |-  ( B  =  C  -> inf ( A ,  B ,  R
)  = inf ( A ,  C ,  R
) )
Colors of variables: wff set class
Syntax hints:    -> wi 4    = wceq 1335   `'ccnv 4582   supcsup 6918  infcinf 6919
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 699  ax-5 1427  ax-7 1428  ax-gen 1429  ax-ie1 1473  ax-ie2 1474  ax-8 1484  ax-10 1485  ax-11 1486  ax-i12 1487  ax-bndl 1489  ax-4 1490  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-ext 2139
This theorem depends on definitions:  df-bi 116  df-tru 1338  df-nf 1441  df-sb 1743  df-clab 2144  df-cleq 2150  df-clel 2153  df-nfc 2288  df-ral 2440  df-rex 2441  df-rab 2444  df-uni 3773  df-sup 6920  df-inf 6921
This theorem is referenced by: (None)
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