Definition df-subma 20202

Description: Define the submatrices of a square matrix. A submatrix is obtained by deleting a row and a column of the original matrix. Since the indices of a matrix need not to be sequential integers, it does not matter that there may be gaps in the numbering of the indices for the submatrix. The determinants of such submatrices are called the "minors" of the original matrix. (Contributed by AV, 27-Dec-2018.)

Assertion

Ref	Expression
df-subma	⊢ subMat = (𝑛 ∈ V, 𝑟 ∈ V ↦ (𝑚 ∈ (Base‘(𝑛 Mat 𝑟)) ↦ (𝑘 ∈ 𝑛, 𝑙 ∈ 𝑛 ↦ (𝑖 ∈ (𝑛 ∖ {𝑘}), 𝑗 ∈ (𝑛 ∖ {𝑙}) ↦ (𝑖𝑚𝑗)))))

Distinct variable group:   𝑛,𝑟,𝑚,𝑖,𝑗,𝑘,𝑙

Detailed syntax breakdown of Definition df-subma

Step	Hyp	Ref	Expression
1		csubma 20201	. 2 class subMat
2		vn	. . 3 setvar 𝑛
3		vr	. . 3 setvar 𝑟
4		cvv 3173	. . 3 class V
5		vm	. . . 4 setvar 𝑚
6	2	cv 1474	. . . . . 6 class 𝑛
7	3	cv 1474	. . . . . 6 class 𝑟
8		cmat 20032	. . . . . 6 class Mat
9	6, 7, 8	co 6549	. . . . 5 class (𝑛 Mat 𝑟)
10		cbs 15695	. . . . 5 class Base
11	9, 10	cfv 5804	. . . 4 class (Base‘(𝑛 Mat 𝑟))
12		vk	. . . . 5 setvar 𝑘
13		vl	. . . . 5 setvar 𝑙
14		vi	. . . . . 6 setvar 𝑖
15		vj	. . . . . 6 setvar 𝑗
16	12	cv 1474	. . . . . . . 8 class 𝑘
17	16	csn 4125	. . . . . . 7 class {𝑘}
18	6, 17	cdif 3537	. . . . . 6 class (𝑛 ∖ {𝑘})
19	13	cv 1474	. . . . . . . 8 class 𝑙
20	19	csn 4125	. . . . . . 7 class {𝑙}
21	6, 20	cdif 3537	. . . . . 6 class (𝑛 ∖ {𝑙})
22	14	cv 1474	. . . . . . 7 class 𝑖
23	15	cv 1474	. . . . . . 7 class 𝑗
24	5	cv 1474	. . . . . . 7 class 𝑚
25	22, 23, 24	co 6549	. . . . . 6 class (𝑖𝑚𝑗)
26	14, 15, 18, 21, 25	cmpt2 6551	. . . . 5 class (𝑖 ∈ (𝑛 ∖ {𝑘}), 𝑗 ∈ (𝑛 ∖ {𝑙}) ↦ (𝑖𝑚𝑗))
27	12, 13, 6, 6, 26	cmpt2 6551	. . . 4 class (𝑘 ∈ 𝑛, 𝑙 ∈ 𝑛 ↦ (𝑖 ∈ (𝑛 ∖ {𝑘}), 𝑗 ∈ (𝑛 ∖ {𝑙}) ↦ (𝑖𝑚𝑗)))
28	5, 11, 27	cmpt 4643	. . 3 class (𝑚 ∈ (Base‘(𝑛 Mat 𝑟)) ↦ (𝑘 ∈ 𝑛, 𝑙 ∈ 𝑛 ↦ (𝑖 ∈ (𝑛 ∖ {𝑘}), 𝑗 ∈ (𝑛 ∖ {𝑙}) ↦ (𝑖𝑚𝑗))))
29	2, 3, 4, 4, 28	cmpt2 6551	. 2 class (𝑛 ∈ V, 𝑟 ∈ V ↦ (𝑚 ∈ (Base‘(𝑛 Mat 𝑟)) ↦ (𝑘 ∈ 𝑛, 𝑙 ∈ 𝑛 ↦ (𝑖 ∈ (𝑛 ∖ {𝑘}), 𝑗 ∈ (𝑛 ∖ {𝑙}) ↦ (𝑖𝑚𝑗)))))
30	1, 29	wceq 1475	1 wff subMat = (𝑛 ∈ V, 𝑟 ∈ V ↦ (𝑚 ∈ (Base‘(𝑛 Mat 𝑟)) ↦ (𝑘 ∈ 𝑛, 𝑙 ∈ 𝑛 ↦ (𝑖 ∈ (𝑛 ∖ {𝑘}), 𝑗 ∈ (𝑛 ∖ {𝑙}) ↦ (𝑖𝑚𝑗)))))

This definition is referenced by:  submafval  20204