Metamath Proof Explorer


Theorem wrdfd

Description: A word is a zero-based sequence with a recoverable upper limit, deduction version. (Contributed by Thierry Arnoux, 22-Dec-2021)

Ref Expression
Hypotheses wrdfd.n φN=W
wrdfd.w φWWordS
Assertion wrdfd φW:0..^NS

Proof

Step Hyp Ref Expression
1 wrdfd.n φN=W
2 wrdfd.w φWWordS
3 wrdf WWordSW:0..^WS
4 2 3 syl φW:0..^WS
5 1 oveq2d φ0..^N=0..^W
6 5 feq2d φW:0..^NSW:0..^WS
7 4 6 mpbird φW:0..^NS