Metamath Proof Explorer


Theorem hvsub4

Description: Hilbert vector space addition/subtraction law. (Contributed by NM, 17-Oct-1999) (New usage is discouraged.)

Ref Expression
Assertion hvsub4 A B C D A + B - C + D = A - C + B - D

Proof

Step Hyp Ref Expression
1 hvaddcl A B A + B
2 hvaddcl C D C + D
3 hvsubval A + B C + D A + B - C + D = A + B + -1 C + D
4 1 2 3 syl2an A B C D A + B - C + D = A + B + -1 C + D
5 hvsubval A C A - C = A + -1 C
6 5 ad2ant2r A B C D A - C = A + -1 C
7 hvsubval B D B - D = B + -1 D
8 7 ad2ant2l A B C D B - D = B + -1 D
9 6 8 oveq12d A B C D A - C + B - D = A + -1 C + B + -1 D
10 neg1cn 1
11 ax-hvdistr1 1 C D -1 C + D = -1 C + -1 D
12 10 11 mp3an1 C D -1 C + D = -1 C + -1 D
13 12 adantl A B C D -1 C + D = -1 C + -1 D
14 13 oveq2d A B C D A + B + -1 C + D = A + B + -1 C + -1 D
15 hvmulcl 1 C -1 C
16 10 15 mpan C -1 C
17 16 anim2i A C A -1 C
18 hvmulcl 1 D -1 D
19 10 18 mpan D -1 D
20 19 anim2i B D B -1 D
21 17 20 anim12i A C B D A -1 C B -1 D
22 21 an4s A B C D A -1 C B -1 D
23 hvadd4 A -1 C B -1 D A + -1 C + B + -1 D = A + B + -1 C + -1 D
24 22 23 syl A B C D A + -1 C + B + -1 D = A + B + -1 C + -1 D
25 14 24 eqtr4d A B C D A + B + -1 C + D = A + -1 C + B + -1 D
26 9 25 eqtr4d A B C D A - C + B - D = A + B + -1 C + D
27 4 26 eqtr4d A B C D A + B - C + D = A - C + B - D