Theorem 2a1d

Deduction introducing two antecedents. Two applications of a1d. Deduction associated with 2a1 and 2a1i. (Contributed by BJ, 10-Aug-2020.)

Hypothesis
2a1d.1
\( \vdash \varphi \rightarrow \psi \)
Conclusion
\( \vdash \varphi \rightarrow \chi \rightarrow \theta \rightarrow \psi \)
Proof
2a1d.1
a1d _
a1d _