Definition df-sets 15864

Description: Set a component of an extensible structure. This function is useful for taking an existing structure and "overriding" one of its components. For example, df-ress 15865 adjusts the base set to match its second argument, which has the effect of making subgroups, subspaces, subrings etc. from the original structures. Or df-mgp 18490, which takes a ring and overrides its addition operation with the multiplicative operation, so that we can consider the "multiplicative group" using group and monoid theorems, which expect the operation to be in the +g slot instead of the .r slot. (Contributed by Mario Carneiro, 1-Dec-2014.)

Assertion

Ref	Expression
df-sets	|- sSet = ( s e. _V , e e. _V |-> ( ( s |` ( _V \ dom { e } ) ) u. { e } ) )

Distinct variable group:   e, s

Detailed syntax breakdown of Definition df-sets

Step	Hyp	Ref	Expression
1		csts 15855	. 2 class sSet
2		vs	. . 3 setvar s
3		ve	. . 3 setvar e
4		cvv 3200	. . 3 class _V
5	2	cv 1482	. . . . 5 class s
6	3	cv 1482	. . . . . . . 8 class e
7	6	csn 4177	. . . . . . 7 class { e }
8	7	cdm 5114	. . . . . 6 class dom { e }
9	4, 8	cdif 3571	. . . . 5 class ( _V \ dom { e } )
10	5, 9	cres 5116	. . . 4 class ( s |` ( _V \ dom { e } ) )
11	10, 7	cun 3572	. . 3 class ( ( s |` ( _V \ dom { e } ) ) u. { e } )
12	2, 3, 4, 4, 11	cmpt2 6652	. 2 class ( s e. _V , e e. _V |-> ( ( s |` ( _V \ dom { e } ) ) u. { e } ) )
13	1, 12	wceq 1483	1 wff sSet = ( s e. _V , e e. _V |-> ( ( s |` ( _V \ dom { e } ) ) u. { e } ) )

This definition is referenced by:  reldmsets  15886  setsvalg  15887