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Jan
23
comment Proofs without words
Also, I am afraid you have misunderstood me. If I were to post a truth-tree for some logical tautology, well that would be a literal example of a "proof without words"; but, you would surely reject it as a non-example. Hence what you really mean is not "proof without words" but "proof without logic."
Jan
23
comment Proofs without words
@MarianoSuárez-Alvarez, oh the concept is well-known alright; these useless so-called "proofs without words" are all over YouTube, usually paired with a lot of downvotes, and rightly so. Its sad that so much effort went into discovering these beautiful arguments, and then producing pictures and even animations to illustrate the idea, only to have all that hard work spoilt by this proof without words nonsense. How much better those so-called "proofs" would have been with a few premises, some inferences, and a conclusion.
Jan
23
comment Proofs without words
There is no such thing as a "proof without logic," and since words are usually the best tool for conveying logical relations, I'm going to have to reject the idea of "proof without words." Sorry, -1.
Jan
23
revised Extensional theorems mostly used intensionally
added 523 characters in body
Jan
23
answered Extensional theorems mostly used intensionally
Jan
19
accepted Looking for interesting, natural models of this algebraic theory in which $x^\dagger$ is not always the multiplicative inverse of $x$
Jan
15
revised Has this construction, which builds a symmetric multicategory from a commutative monoid, been described or studied anywhere, and if so, where?
added 1 character in body
Jan
15
revised Has this construction, which builds a symmetric multicategory from a commutative monoid, been described or studied anywhere, and if so, where?
added 137 characters in body
Jan
15
revised Has this construction, which builds a symmetric multicategory from a commutative monoid, been described or studied anywhere, and if so, where?
edited body
Jan
15
asked Has this construction, which builds a symmetric multicategory from a commutative monoid, been described or studied anywhere, and if so, where?
Dec
29
revised Looking for interesting, natural models of this algebraic theory in which $x^\dagger$ is not always the multiplicative inverse of $x$
Replaced additive notation with multiplicative notation to better reflect the notation of the original question
Dec
29
suggested approved edit on Looking for interesting, natural models of this algebraic theory in which $x^\dagger$ is not always the multiplicative inverse of $x$
Dec
27
comment Looking for interesting, natural models of this algebraic theory in which $x^\dagger$ is not always the multiplicative inverse of $x$
@GeraldEdgar, yes, that is what I mean.
Dec
26
comment Looking for interesting, natural models of this algebraic theory in which $x^\dagger$ is not always the multiplicative inverse of $x$
Another observation is that $x^\dagger = x$ doesn't give anything interesting, because this forces meets to coincide with joins, by 7 or 8.
Dec
26
comment Looking for interesting, natural models of this algebraic theory in which $x^\dagger$ is not always the multiplicative inverse of $x$
This is not involutive.
Dec
26
revised Looking for interesting, natural models of this algebraic theory in which $x^\dagger$ is not always the multiplicative inverse of $x$
added 33 characters in body
Dec
26
asked Looking for interesting, natural models of this algebraic theory in which $x^\dagger$ is not always the multiplicative inverse of $x$
Dec
19
comment Arguments against large cardinals
@StefanGeschke, this reminds me of the "obviousness" of the consistency of unrestricted comprehension. In some sense, it was SUCH a natural axiom schema, it couldn't possibly be consistent. Some things are too perfect to be true.
Sep
30
comment What is the most useful non-existing object of your field?
This is sometimes called the Russell set, or Russell class. Its so dangerous, even NFU blocks it.
Aug
30
awarded  Yearling