Metamath Proof Explorer


Theorem satf00

Description: The value of the satisfaction predicate as function over wff codes in the empty model with an empty binary relation at (/) . (Contributed by AV, 14-Sep-2023)

Ref Expression
Assertion satf00 Sat=xy|y=iωjωx=i𝑔j

Proof

Step Hyp Ref Expression
1 peano1 ω
2 elelsuc ωsucω
3 satf0sucom sucωSat=recfVfxy|y=ufvfx=1stu𝑔1stviωx=𝑔i1stuxy|y=iωjωx=i𝑔j
4 1 2 3 mp2b Sat=recfVfxy|y=ufvfx=1stu𝑔1stviωx=𝑔i1stuxy|y=iωjωx=i𝑔j
5 omex ωV
6 5 5 xpex ω×ωV
7 xpexg ωVω×ωVω×ω×ωV
8 simpl ωVω×ωVωV
9 goelel3xp iωjωi𝑔jω×ω×ω
10 eleq1 x=i𝑔jxω×ω×ωi𝑔jω×ω×ω
11 9 10 syl5ibrcom iωjωx=i𝑔jxω×ω×ω
12 11 rexlimivv iωjωx=i𝑔jxω×ω×ω
13 12 ad2antll ωVω×ωVy=iωjωx=i𝑔jxω×ω×ω
14 eleq1 y=yωω
15 1 14 mpbiri y=yω
16 15 ad2antrl ωVω×ωVy=iωjωx=i𝑔jyω
17 7 8 13 16 opabex2 ωVω×ωVxy|y=iωjωx=i𝑔jV
18 5 6 17 mp2an xy|y=iωjωx=i𝑔jV
19 18 rdg0 recfVfxy|y=ufvfx=1stu𝑔1stviωx=𝑔i1stuxy|y=iωjωx=i𝑔j=xy|y=iωjωx=i𝑔j
20 4 19 eqtri Sat=xy|y=iωjωx=i𝑔j