Theorem bdcun 15997

Description: The union of two bounded classes is bounded. (Contributed by BJ, 3-Oct-2019.)

Hypotheses

Ref	Expression
bdcdif.1	|- BOUNDED A
bdcdif.2	|- BOUNDED B

Assertion

Ref	Expression
bdcun	|- BOUNDED ( A u. B )

Proof of Theorem bdcun

Dummy variable x is distinct from all other variables.

Step	Hyp	Ref	Expression
1		bdcdif.1	. . . . 5 |- BOUNDED A
2	1	bdeli 15981	. . . 4 |- BOUNDED x e. A
3		bdcdif.2	. . . . 5 |- BOUNDED B
4	3	bdeli 15981	. . . 4 |- BOUNDED x e. B
5	2, 4	ax-bdor 15951	. . 3 |- BOUNDED ( x e. A \/ x e. B )
6	5	bdcab 15984	. 2 |- BOUNDED { x | ( x e. A \/ x e. B ) }
7		df-un 3178	. 2 |- ( A u. B ) = { x | ( x e. A \/ x e. B ) }
8	6, 7	bdceqir 15979	1 |- BOUNDED ( A u. B )

Syntax hints:   \/ wo 710   e. wcel 2178   {cab 2193   u. cun 3172  BOUNDED wbdc 15975

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1471  ax-gen 1473  ax-ie1 1517  ax-ie2 1518  ax-4 1534  ax-17 1550  ax-ial 1558  ax-ext 2189  ax-bd0 15948  ax-bdor 15951  ax-bdsb 15957

This theorem depends on definitions:  df-bi 117  df-clab 2194  df-cleq 2200  df-clel 2203  df-un 3178  df-bdc 15976

This theorem is referenced by:  bdcpr  16006  bdctp  16007  bdcsuc  16015