Metamath Proof Explorer


Theorem efnnfsumcl

Description: Finite sum closure in the log-integers. (Contributed by Mario Carneiro, 7-Apr-2016)

Ref Expression
Hypotheses efnnfsumcl.1 φAFin
efnnfsumcl.2 φkAB
efnnfsumcl.3 φkAeB
Assertion efnnfsumcl φekAB

Proof

Step Hyp Ref Expression
1 efnnfsumcl.1 φAFin
2 efnnfsumcl.2 φkAB
3 efnnfsumcl.3 φkAeB
4 ssrab2 x|ex
5 ax-resscn
6 4 5 sstri x|ex
7 6 a1i φx|ex
8 fveq2 x=yex=ey
9 8 eleq1d x=yexey
10 9 elrab yx|exyey
11 fveq2 x=zex=ez
12 11 eleq1d x=zexez
13 12 elrab zx|exzez
14 fveq2 x=y+zex=ey+z
15 14 eleq1d x=y+zexey+z
16 simpll yeyzezy
17 simprl yeyzezz
18 16 17 readdcld yeyzezy+z
19 16 recnd yeyzezy
20 17 recnd yeyzezz
21 efadd yzey+z=eyez
22 19 20 21 syl2anc yeyzezey+z=eyez
23 nnmulcl eyezeyez
24 23 ad2ant2l yeyzezeyez
25 22 24 eqeltrd yeyzezey+z
26 15 18 25 elrabd yeyzezy+zx|ex
27 10 13 26 syl2anb yx|exzx|exy+zx|ex
28 27 adantl φyx|exzx|exy+zx|ex
29 fveq2 x=Bex=eB
30 29 eleq1d x=BexeB
31 30 2 3 elrabd φkABx|ex
32 0re 0
33 1nn 1
34 fveq2 x=0ex=e0
35 ef0 e0=1
36 34 35 eqtrdi x=0ex=1
37 36 eleq1d x=0ex1
38 37 elrab 0x|ex01
39 32 33 38 mpbir2an 0x|ex
40 39 a1i φ0x|ex
41 7 28 1 31 40 fsumcllem φkABx|ex
42 fveq2 x=kABex=ekAB
43 42 eleq1d x=kABexekAB
44 43 elrab kABx|exkABekAB
45 44 simprbi kABx|exekAB
46 41 45 syl φekAB