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| Mirrors > Home > MPE Home > Th. List > unssd | Structured version Visualization version Unicode version | ||
| Description: A deduction showing the union of two subclasses is a subclass. (Contributed by Jonathan Ben-Naim, 3-Jun-2011.) |
| Ref | Expression |
|---|---|
| unssd.1 |
|
| unssd.2 |
|
| Ref | Expression |
|---|---|
| unssd |
|
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | unssd.1 |
. 2
| |
| 2 | unssd.2 |
. 2
| |
| 3 | unss 3787 |
. . 3
| |
| 4 | 3 | biimpi 206 |
. 2
|
| 5 | 1, 2, 4 | syl2anc 693 |
1
|
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