Metamath Proof Explorer


Theorem shftf

Description: Functionality of a shifted sequence. (Contributed by NM, 19-Aug-2005) (Revised by Mario Carneiro, 5-Nov-2013)

Ref Expression
Hypothesis shftfval.1 FV
Assertion shftf F:BCAFshiftA:x|xABC

Proof

Step Hyp Ref Expression
1 shftfval.1 FV
2 ffn F:BCFFnB
3 1 shftfn FFnBAFshiftAFnx|xAB
4 2 3 sylan F:BCAFshiftAFnx|xAB
5 oveq1 x=yxA=yA
6 5 eleq1d x=yxAByAB
7 6 elrab yx|xAByyAB
8 simpr F:BCAA
9 simpl yyABy
10 1 shftval AyFshiftAy=FyA
11 8 9 10 syl2an F:BCAyyABFshiftAy=FyA
12 simpl F:BCAF:BC
13 simpr yyAByAB
14 ffvelcdm F:BCyABFyAC
15 12 13 14 syl2an F:BCAyyABFyAC
16 11 15 eqeltrd F:BCAyyABFshiftAyC
17 7 16 sylan2b F:BCAyx|xABFshiftAyC
18 17 ralrimiva F:BCAyx|xABFshiftAyC
19 ffnfv FshiftA:x|xABCFshiftAFnx|xAByx|xABFshiftAyC
20 4 18 19 sylanbrc F:BCAFshiftA:x|xABC