Different ways to express If-Then
What are some different ways to write the conditional statement $p\implies q\,$, but in English?
There's the obvious "If p, then q", but are there any other ways to write it? I'm looking for another 3 or 4 ways to express this.
Solution 1:
Different ways to write, or express, the conditional statement $p \rightarrow q$ besides "if $p$ then $q$."
- "$p$ is a sufficient condition for $q$"; or
- "$p$ only if $q$";
- "$p$ implies $q$";
- "$q$ whenever $p$"
- "$q$ is a necessary condition for $p$" (i.e., "if not $q$, then not $p$", or $\lnot q \rightarrow \lnot p$);
- "$q$ is a consequence of $p$";
- "$q$ follows from $p$";
- "$q$ if $p$".
- "if not $q$, then not $p$."
- "not $p$, or $q$"
- "not ($p$ and not $q$)
Logically, we can write $(10)$ as $$(p \rightarrow q) \equiv (\lnot p \lor q)$$ and $(11)$ as $$(p \rightarrow q) \equiv \lnot(p \land \lnot q)$$
Those are just a few of the ways one can express "if $p$, then $q$." But some expressions may be more intuitive than others.
One final note: The term "unless" also relates to "if and only if" in the following sense: as in "$p$ unless $q$" is equivalent to "unless $q$, then $p$" which is equivalent to "if not $q$, then $p$".
Solution 2:
"p only if q"
"q whenever p"
"q if p"
"q is a necessary condition for p"
"q unless not p"
Solution 3:
The proposition $P\Rightarrow Q$ is logically equivalent to
$$\sim P \vee Q.$$