Metamath Proof Explorer


Definition df-ipf

Description: Define the inner product function. Usually we will use .i directly instead of .if , and they have the same behavior in most cases. The main advantage of .if is that it is a guaranteed function ( ipffn ), while .i only has closure ( ipcl ). (Contributed by Mario Carneiro, 12-Aug-2015)

Ref Expression
Assertion df-ipf if = g V x Base g , y Base g x 𝑖 g y

Detailed syntax breakdown

Step Hyp Ref Expression
0 cipf class if
1 vg setvar g
2 cvv class V
3 vx setvar x
4 cbs class Base
5 1 cv setvar g
6 5 4 cfv class Base g
7 vy setvar y
8 3 cv setvar x
9 cip class 𝑖
10 5 9 cfv class 𝑖 g
11 7 cv setvar y
12 8 11 10 co class x 𝑖 g y
13 3 7 6 6 12 cmpo class x Base g , y Base g x 𝑖 g y
14 1 2 13 cmpt class g V x Base g , y Base g x 𝑖 g y
15 0 14 wceq wff if = g V x Base g , y Base g x 𝑖 g y