Given a new unsorted example, there is no universal way of finding out which side it fits on, yet, although one does not know where to look, noticing something new may show the example fits left vs. not so.

Given a new unsorted example, there is no universal way of finding out which side it fits on, yet, although one does not know where to look, noticing something new may show the example fits left vs. other Bongard Problems.

A person (who knows the solution) might be given a new unsorted example such that there is no clear way of finding out which side it fits on, and, although they do not know where to look, perhaps noticing something new will show the example fits left vs. other Bongard Problems.

A person (who knows the solution) might be given a new unsorted example such that there is no clear way of finding out which side it fits on, and, although they do not know where to look, perhaps noticing some new aspect will show the example fits left vs. other Bongard Problems.

Bongard Problems such that a person (who knows the solution) might be given a new unsorted example, and although they do not know where to look (there is no clear way of finding out which side it should go on), perhaps noticing some new aspect will show the example fits left vs. other Bongard Problems.

Bongard Problems such that a person (who knows the solution) might be given a new unsorted example and have no clear way of finding out which side it should go on, and although they do not know where to look, perhaps noticing some new thing will show the example fits left vs. other Bongard Problems.

Bongard Problems such that a person (who knows the solution) might be given a new unsorted example and have no clear way of finding out how it should be sorted, and although they do not know where to look, perhaps noticing some new thing will show the example fits left vs. other Bongard Problems.

Bongard Problems such that a person (who knows the solution) might be given a new unsorted example and have no way of finding out how it should be sorted--however, there is the potential to notice something new that convinces them it fits left vs. other Bongard Problems.

Left-sorted Bongard Problems have the keyword "left-noticed" on the OEBP.

Another way of phrasing "left-noticed" that there is no (obvious) general method to determine a left-fitting example fits left, although some examples can indeed be seen to fit left.

There is a similar idea in computability theory: a "non recursively enumerable" property is one that cannot be checked in general by a computer algorithm.

Here, "noticed" is supposed to mean something less formal. For example, it is easy for a human being to check when a simple shape is convex or concave, so BP4 is not labelled "left-noticed". However, it is not as if we use an algorithm to do this, like a computer. (It is not even clear what sort of algorithm we would be looking for, since it is it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

See "right-noticed" (left-BP1127).

"Noticed" Bongard Problems are also "hardsort" (right-BP864).

Left-sorted Bongard Problems have the keyword "left-noticed" on the OEBP.

Another way of phrasing "left-noticed" that there is no (obvious) general method to determine a left-fitting example fits left, although some examples can indeed be seen to fit left.

There is a similar idea in computability theory: a "non recursively enumerable" property is one that cannot be checked in general by a computer algorithm.

Here, "noticeable" is supposed to mean something less formal. For example, it is easy for a human being to check when a simple shape is convex or concave, so BP4 is not labelled "left-noticed". However, it is not as if we use an algorithm to do this, like a computer. (It is not even clear what sort of algorithm we would be looking for, since it is it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

Left-sorted Bongard Problems have the keyword "left-noticed" on the OEBP.

Another way of phrasing "left-noticed" that there is no (obvious) general method to determine a left-fitting example fits left.

There is a similar idea in computability theory: a "non recursively enumerable" property is one that cannot be checked in general by a computer algorithm.

Here, "noticeable" is supposed to mean something less formal. For example, it is easy for a human being to check when a simple shape is convex or concave, so BP4 is not labelled "left-noticed". However, it is not as if we use an algorithm to do this, like a computer. (It is not even clear what sort of algorithm we would be looking for, since it is it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

Bongard Problems such that a person (who knows the solution) might be given a new unsorted example and have no way of finding out how it should be sorted--however, there is the potential for them to notice something new that convinces them it fits left vs. other Bongard Problems.

Left-sorted Bongard Problems have the keyword "left-noticed" on the OEBP.

Another way of phrasing "left-noticed" that there is no (obvious) general method to determine a left-fitting example fits left.

There is a similar idea in computability theory: a "non recursively enumerable" property is one that cannot be checked in general by a computer algorithm.

Here, "noticeable" is supposed to mean be less formal. For example, it is easy for a human being to check when a simple shape is convex or concave, so BP4 is not labelled "left-noticed". However, it is not as if we use an algorithm to do this, like a computer. (It is not even clear what sort of algorithm we would be looking for, since it is it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

See "right-noticed" (left-BP1127).

Undecidable Bongard Problems are also "hardsort" (right-BP864).

We say "tessellates the plane vs. does not tessellate the plane" (BP335) is left-noticed, since not only is it difficult to determine some shapes go left (see keyword "hardsort" left-BP864), but there does not even exist a method of checking; one has to notice (by ingenuity) a proof.

Left-sorted Bongard Problems have the keyword "left-undecidable" on the OEBP.

Another way to phrase "left-undecidable" is that there is potential for someone to have the unsure hunch an example should be sorted right, but noticing something could convince them otherwise.

This is meant to be an informal label.

It is easy for a human being to check when a simple shape is convex or concave, so BP4 is not labelled "left-undecidable", but it is not as if we use an algorithm to do this, like a computer. (It is not even clear what sort of algorithm we would be looking for, since it is it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

On the other hand we say "tessellates the plane vs. does not tessellate the plane" (BP335) is left-undecidable, since not only is it difficult to determine some shapes go left (see keyword "hardsort" right-BP864), but there does not even exist a method of checking; one has to notice (by ingenuity) a proof.

Left-sorted Bongard Problems have the keyword "left-undecidable" on the OEBP.

This is meant to be an informal label.

It is easy for a human being to check when a simple shape is convex or concave, so BP4 is not labelled "left-undecidable", but it is not as if we use an algorithm to do this, like a computer. (It is not even clear what sort of algorithm we would be looking for, since it is it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

On the other hand we say "tessellates the plane vs. does not tessellate the plane" (BP335) is left-undecidable, since not only is it difficult to determine some shapes go left (see keyword "hardsort" right-BP864), but there does not even exist a method of checking; one has to notice (by ingenuity) a proof.

Left-sorted Bongard Problems have the keyword "left-undecidable" on the OEBP.

This is meant to be an informal label.

It is easy for a human being to check when a simple shape is convex or concave, so BP4 is not labelled "left-undecidable", but it is not as if we use a particular algorithm. (It is not even clear what sort of algorithm we would be looking for, since it is it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

On the other hand we say "tessellates the plane vs. does not tessellate the plane" (BP335) is left-undecidable, since not only is it difficult to determine some shapes go left (see keyword "hardsort" right-BP864), but there does not even exist a method of checking; one has to notice (by ingenuity) a proof.

Left-sorted Bongard Problems have the keyword "left-undecidable" on the OEBP.

This is meant to be an informal label.

On the other hand we say "tessellates the plane vs. does not tessellate the plane" (BP335) is left-undecidable, since it is, in any case, very difficult to determine some shapes go left. While no general algorithm is known for determining whether or not a tile tessellates the plane, we are not aware of a proof that such an algorithm is impossible. (It is not even clear what sort of algorithm we would be looking for, since it is it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

A more strict (less "fuzzy" right-BP508) definition of "left-undecidable" would require us to be certain there exists no foolproof sorting method, rather than just that the average solver won't come up with one. See keyword "weakhardsort" (left-BP1125) for more on this topic.

Left-sorted Bongard Problems have the keyword "left-undecidable" on the OEBP.

This is meant to be an informal label.

Likewise we say BP335 ("tessellates the plane vs. does not tessellate the plane") is left-undecidable, since it is, in any case, very difficult to determine some shapes go left. While no general algorithm is known for determining whether or not a tile tessellates the plane, we are not aware of a proof that such an algorithm is impossible. (It is not even clear what sort of algorithm we would be looking for, since it is it is ambiguous both what class of shapes the Bongard Problem sorts and how that would be encoded into a computer program's input. There are usually many options and ambiguities like this whenever one tries to formalize the content of a Bongard Problem.)

A more strict (less "fuzzy" right-BP508) definition of "left-undecidable" would require us to be certain there exists no foolproof sorting method, rather than just that the average solver won't come up with one. See keyword "weakhardsort" (left-BP1125) for more on this topic.

Left-sorted Bongard Problems have the keyword "left-undecidable" on the OEBP.

This is meant to be an informal label. We say BP335 ("tessellates the plane vs. does not tessellate the plane") is left-undecidable, since it is, in any case, very difficult to determine some shapes go left. While no general algorithm is known for determining whether or not a tile tessellates the plane, we are not aware of a proof that such an algorithm is impossible.

A more strict (less "fuzzy" right-BP508) definition of "left-undecidable" would require us to be certain there exists no foolproof sorting method, rather than just that the average solver won't come up with one. See keyword "weakhardsort" (left-BP1125) for more on this topic.

Left-sorted Bongard Problems have the keyword "left-undecidable" on the OEBP.

No general algorithm is known for determining whether or not a tile tessellates the plane. However, we are not aware of a proof that such an algorithm is impossible. Even so, we say BP335 ("tessellates the plane vs. does not tessellate the plane") is left-undecidable, since it is, in any case, very difficult to determine some shapes go left.

A more strict (less "fuzzy" right-BP508) definition of "left-undecidable" would require us to be certain there exists no foolproof sorting method, rather than just that the average solver won't come up with one. See keyword "weakhardsort" (left-BP1125) for more on this topic.

See "right-undecidable" (left-BP1127).

Undecidable Bongard Problems are also "hardsort" (right-BP864).

Left-sorted Bongard Problems have the keyword "left-undecidable" on the OEBP.

No general algorithm is known for determining whether or not a tile tessellates the plane. However, we are not aware of a proof that such an algorithm is impossible. Even so, we say BP335 ("tessellates the plane vs. does not tessellate the plane") is left-undecidable, since it is, in any case, very difficult to determine some shapes go left.

A more strict (less "fuzzy" right-BP508) definition of "left-undecidable" might require us to be certain there exists no foolproof sorting method, rather than just that the average solver won't come up with one. See keyword "weakhardsort" (left-BP1125) for more on this topic.

See "right-undecidable" (left-BP1127).

Uncertain Bongard Problems are also "hardsort" (right-BP864).

See "right-uncertain" (left-BP1127).

Uncertain Bongard Problems are also "hardsort" (right-BP864).

See "right-uncertain" (left-BP1127).

Left-sorted Bongard Problems have the keyword "left-uncertain" on the OEBP.

(Right-sorted Bongard Problems might be called "semi-decidable" for the property of being sorted left, in computability lingo, but this is less formal.)

No general algorithm is known for determining whether or not a tile tessellates the plane. However, we are not aware of a proof that such an algorithm is impossible. Even so, we say BP335 ("tessellates the plane vs. does not tessellate the plane") is left-uncertain, since it is, in any case, very difficult to determine some shapes go left.

A more strict (less "fuzzy" right-BP508) definition of "left-uncertain" might require us to be certain there exists no foolproof sorting method, rather than just that the average solver won't come up with one. See keyword "weakhardsort" (left-BP1125) for more on this topic.

Left-sorted Bongard Problems have the keyword "left-uncertain" on the OEBP.

(Right-sorted Bongard Problems might be called "semi-decidable" in computability lingo, but this is less formal.)

No general algorithm is known for determining whether or not a tile tessellates the plane. However, we are not aware of a proof that such an algorithm is impossible. Even so, we say BP335 ("tessellates the plane vs. does not tessellate the plane") is left-uncertain, since it is, in any case, very difficult to determine some shapes go left.

A more strict (less "fuzzy" right-BP508) definition of "left-uncertain" might require us to be certain there exists no foolproof sorting method, rather than just that the average solver won't come up with one. See keyword "weakhardsort" (left-BP1125) for more on this topic.