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Metamath Proof Explorer


Theorem ordtr1

Description: Transitive law for ordinal classes. (Contributed by NM, 12-Dec-2004)

Ref Expression
Assertion ordtr1 Ord C A B B C A C

Proof

Step Hyp Ref Expression
1 ordtr Ord C Tr C
2 trel Tr C A B B C A C
3 1 2 syl Ord C A B B C A C