Metamath Proof Explorer


Theorem resabs1d

Description: Absorption law for restriction, deduction form. (Contributed by Glauco Siliprandi, 11-Dec-2019)

Ref Expression
Hypothesis resabs1d.b φBC
Assertion resabs1d φACB=AB

Proof

Step Hyp Ref Expression
1 resabs1d.b φBC
2 resabs1 BCACB=AB
3 1 2 syl φACB=AB